FAQ: Mass Air Flow (MAF) Sensor Issues?

Some info from AA1car.com (Ford article):

Ford P0171 & P0174 Lean Codes

A Ford P0171 is a LEAN code fpr cylinder bank 1, and P0174 is a LEAN code for cylinder bank 2. These codes commonly occur on many Ford vehicles, and are set when the powertrain control module (PCM) sees the air/fuel mixture is running too lean (too much air, not enough fuel).

When the Check Engine Light comes on, either one of these codes, or both, may be found when a code reader or scan tool is plugged into the vehicle diagnostic connector. IF the vehicle is driven long enough, typically both codes will be set.

A P0171 lean code for bank 1 is the cylinder bank on the RIGHT (passenger) side of the engine on Ford vehicles with a V6 or V8 engine and rear-wheel drive.

A P0174 lean code for bank 2 is the cylinder bank on the LEFT (driver) side of the engine on Ford vehicles with a transverse-mounted V6 engine and front-wheel drive. This code is not set on four cylinder engines (no bank 2).

WHAT A LEAN CODE MEANS

A lean fuel condition may exist if the engine is sucking in too much air and/or the fuel system is not delivering enough fuel. If bad enough, a lean fuel condition may cause lean misfire, a rough idle, hesitation or stumble when accelerating, and/or poor engine performance.

Unmetered air can enter the engine through a vacuum leak, a dirty airflow sensor that is not reading airflow accurately, an EGR valve is not closing and is leaking exhaust into the intake manifold, an EGR valve that is allowing too much flow (because the EGR differential pressure sensor that monitors EGR flow is faulty and is under-reporting EGR flow).

If the problem is not enough fuel, the underling cause may be a weak fuel pump, restricted fuel filter, leaky fuel pressure regulator or dirty fuel injectors.

DIRTY MAF SENSOR

One of the most common causes of Ford P0171 and P0174 lean codes is a dirty mass airflow (MAF) sensor. The MAF sensor is located in the air inlet tube Ford MAF sensor just ahead of the throttle body. The MAF sensor should be protected from outside dust and debris by the air filter, but sometimes the air filter doesn't fit real tight inside the housing and allows unfiltered air into the engine. Dirt can stick to the MAF sensor wire and form a coating that slows the response of the sensor to changes in airflow. The MAF sensor can also be contaminated by fuel vapors that back up through the intake manifold and throttle body when the engine is shut off. The vapors can leave a waxy coating on the sensor wire. This causes the MAF sensor to under report airflow, which in turn misleads the powertrain control module (PCM) so it doesn't add enough fuel to maintain a properly balanced air/fuel ratio. As a result, the engine runs lean and sets a P0171 and/or P0174 code (see Ford TSB 98-23-10 for details).

If the MAF is dirty, the fix is easy enough: just clean or replace the MAF sensor. In many instances, the MAF sensor can be successfully cleaned by spraying the sensor element with electronics cleaner. Do not use any other type of cleaner as this may damage the sensor.

Disconnect the air inlet tube just ahead of the sensor, and then spray the electronics cleaner through the screen at the wire element in the center of the little MAF sensor. Let the cleaner soak in for several minutes, then give it another shot of cleaner. Let it sit another five minutes, then reconnect the air inlet tubing and start the engine.

If the lean codes keep coming back, the MAF sensor may have to be replaced if the engine does not have a vacuum leak or fuel delivery problem.

VACUUM LEAKS

Another common cause of Ford P0171 and P0174 ean codes is an engine vacuum leak. Ford TSB 04-17-4 details procedures for checking fuel trim and looking for vacuum leaks.

Ford fuel pressure regulator On 3.8L Fords with a split-plenum intake manifold, the port gaskets and isolator bolt assemblies for the upper plenum can deteriorate over time and leak air, often as a result of oil being sucked into the intake manifold through the PCV system. Also the vacuum hose that connects the fuel pressure regulator to the intake manifold can swell and leak vacuum where the hose connects to the manifold. Ford TSB 03-16-1 says the fix involves several steps: remove the upper manifold plenum and replace the original gaskets and bolts with revised ones, replace the front valve cover with a revised valve cover that reduces the amount of oil vapor sucked into the PCV system, inspect and replace the fuel pressure regulator hose, and finally, reflash the PCM so it is less sensitive to lean fuel conditions.

BAD DPFE SENSOR

Ford p0171 AND p0174 lean codes can also be set by a bad EGR differential pressure sensor. These sensors have a very high failure rate once a vehicle has more than about 60,000 miles on the odometer or is more than five or six years old.

Ford DPFE sensor The DPFE sensor is mounted on the engine, and is attached with two rubber hoses to the tube that routes exhaust gas to the EGR valve. The original equipment sensor has an rectangular aluminum housing about three inches long. Corrosion inside the sensor reduces its sensitivity to EGR flow, causing it to under-report EGR flow. The PCM responds by increasing EGR flow, which may keep the EGR valve open longer than usual creating a lean condition in the engine. Thus, a bad sensor may set a P0401 code (insufficient EGR flow), or it may not set an EGR code but a P0171 and/or P0174 lean code instead.

The cause of the P0401 code in most cases turns out to be a bad DPFE sensor, not an EGR valve problem or an EGR valve that is plugged up with carbon (though this can also set a P0401 code). An aftermarket replacement DPFE sensor costs less than $50 and usually gets rid of not only the P0401 code, but also the P0171 and P0174 codes, too.

Link: http://www.aa1car.com/library/ford_lean_codes.htm
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From OBD-Codes.com:

P0171 OBD-II Trouble Code: System Too Lean (Bank 1) - What does that mean?

Basically this means that an oxygen sensor in bank 1 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1.

Note: This DTC is very similar to P0174, and in fact your vehicle may show both codes at the same time.
Symptoms

You will more than likely not notice any drivability problems, although there may be symptoms such as a lack of power, detonation (spark knock), and/or a hesitation/surge on acceleration.
Causes

A code P0171 may mean that one or more of the following has happened:

* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
* There could be a vacuum leak downstream of the MAF sensor.

Possible solutions include:

* In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect all vacuum and PCV hoses, replace if necessary
* Check for a dirty fuel filter and proper fuel pressure

Link: http://www.obd-codes.com/p0171
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From 2carpros.com:

Lean Mixture Codes (P0171 or P0174 on some manufacturers)

Introduction

The engine management system is designed to control the air fuel mixture the engine consumes. This system controls the air fuel mixture according to sensor feedback data. There are two types of lean mixture conditions, computer controlled and non-computer controlled malfunctions. Also, there is a different diagnosis if there is lean mixture codes for one side or the other of the exhaust system, bank 1 or bank 2 (V10 V8 V6 only) and a lean codes for both sides of the exhaust system. If there is a lean mixture code for one bank or the other it typically means an engine cylinder or injector is having a problem. On this page there are two sections; Section 1 is for lean bank 1 or bank 2. Section 2 is for lean system codes (lean on both sides, bank 1 and 2). Common misconception: When an engine miss-fires it creates a lean condition not a rich one and this is why all engines run on an optimum fuel to air mixture called "stoichiometric" which means chemically balanced. This balanced fuel to air ratio is 14.7 to 1, 14.7 parts air to 1 part fuel. When the engine misfires it releases more air (14.7 times more) then fuel, creating a lean mixture. When a lean mixture code is present you must consider how the engine is running before diagnosis begins. We have listed the most common reasons for a lean mixture code below:

Car Repair Guide - READ COMPLETELY!

Section 1 - Lean mixture code for bank 1 or bank 2 (V6,V8,V10 and V12 engine only)

* Step 1 - Use a simple scanner tool to retrieve trouble codes and check if they relate to a specific cylinder, like an ignition coil or fuel injector failure code and repair as needed. Once the repairs have been made clear the trouble codes and recheck system. If a trouble code is present but does not pertain to the immediate problem like an EVAP failure code it must be checked. The reason we repair non-related codes is if the component is vacuum driven, it might be leaking causing a lean mixture code. If no trouble codes (besides the lean mixture codes) are present proceed to the next step.

* Step 2 - If your engine is running rough with no additional trouble codes it will produce a lean mixture DTC (diagnostic trouble code). You must determine what is causing the engine misfire. Please follow this link to troubleshoot the problem, Why does my engine run rough? If your engine is running ok proceed to the next step.

* Step 3 - The exhaust system is used to transfer exhaust gases to the rear of the vehicle. If an exhaust leak is present before the oxygen sensors it can cause the sensor to produce a false reading. You might say a leak will not affect the reading because the exhaust is simply leaking out. The problem is that theory is not exactly true. Engine exhaust is produced in pulses as the cylinder's fire. When the exhaust valve opens pressure is created in the exhaust system while the spent mixture exits the combustion chamber. But then a vacuum condition in the exhaust is created after the exhaust valve closes. This vacuum condition can draw raw oxygen from outside of the system and cause a false reading. To inspect for an exhaust leak, start with a cold engine. Then have a helper start the engine and hold the idle at about 1500 rpm. Next, try to listen for any exhaust noises coming from any part of the exhaust system including the exhaust manifold and head pipe. Also look for black soot at any point in the system as this can be the source of an exhaust leak. If an exhaust leak is detected repair leak and recheck system. If no exhaust leak is detected continue to the next step.

* Step 4 - The oxygen (02) sensor is designed to deliver feedback voltage to the PCM/ECM. If the sensing element fails it will not deliver the proper feedback information causing a lean mixture code. To test the oxygen sensor follow this link - How to test an oxygen sensor

Section 2 - Lean mixture code for both bank 1 and bank 2 (lean system code) (bank 1 only on 4 cylinder engines)

(Note: if you have trouble codes for both primary oxygen sensors lean, the chances both sensors have failed are remote. The problem is somewhere else.)

* Step 1 - The correct fuel delivery is essential for proper engine operation. This means if the fuel delivery is impaired for any reason it can cause a lean mixture code. The main reasons for this condition are plugged fuel filter or weak fuel pump operation. To inspect the fuel filter follow this link - How to change a fuel filter. To check the fuel pressure observe the video below:

* Step 2 - Your engine is designed to run on specific values, if there are no codes besides a lean mixture code and the engine is running ok the problem is a sensing value problem. A MAF (mass air flow) sensor is famous for causing such a problem. Example: Let's say the engine is running at 2100 RPM at any particular time. When a MAF fails it sends feedback information to the ECM/PCM that the engine is running at 1800 RPM so the computer will lean down the mixture. But the engine is running at 2100 rpm so the mixture is detected lean by the oxygen sensor and the computer will illuminate the CEL (check engine light). There are a few main reasons the MAF reading can be incorrect. First the air intake boot could be cracked or ripped allowing non-metered engine air intake to be consumed. Or the MAF fails because the sensing element inside the sensor becomes contaminated from impurities from the air the engine consumes. Sometimes this element can be cleaned with an aerosol cleaner such as MAF cleaner. I have had limited success cleaning the MAF sensor, replacement at this point is best. Repair or replace failed components as needed and recheck the system. If your engine does not use a MAF continue to the next step.

* Step 3 - Your engine is designed to run on its ability to hold vacuum. If vacuum is allowed to leak it will cause a lean mixture condition. Vacuum hoses are typically connected to the engine intake manifold and will supply engine vacuum to various accessories like power brakes. Some cars are designed with a larger vacuum transfer hose like Ford that connects the intake manifold to the IAC (idle air control) motor. A broken or dilapidated vacuum line or air intake boot can cause the engine to lose vacuum which will cause a lean mixture code. Inspect all engine and accessory vacuum lines to look for missing, torn or dilapidated lines and replace as needed. Also have a helper rest their foot on the gas pedal just enough to keep the engine running. Check the engine when it is running to listen for any whistling noise coming from the engine that is not usually present. Follow the noise and inspect vacuum lines in that area. In addition when the engine is running it will pull inward a broken or weak piece of the hose to create a larger vacuum leak. Check the integrity of all vacuum hoses at each end of the hose. Typically this is where a vacuum hose fails. Replace any vacuums hoses that have failed, clear codes and recheck system.


Failed Air Intake Boot ^^^

For exact specific repair procedures for any of the steps above visit our car repair manual page.

WARNING! Always have the vehicle under inspection on level ground, in park with the emergency brake on. Always wear protective eyewear, gloves and necessary clothing before inspection or work begins. Never crank an engine over when anyone is near the battery or engine. Always have an operational fire extinguisher close by, obey all first aid instructions in the event of an injury. Never stand in front or behind a vehicle when starting or running. When engine is cranked over keep hands and clothing away from rotating components. Anyone with a heart pacemaker should not perform these tests.

Link:http://www.2carpros.com/first_things/why_does_my_engine_have_a_lean_mixture_code.htm
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From Blazerforum.com:

P0171 - Fuel Trim - System Lean Bank 1

CIRCUIT DESCRIPTION

In order to provide the best possible combination of driveability, fuel economy, and emission control, the vehicle uses a Closed Loop air and fuel metering system. While in closed loop, the VCM monitors the oxygen sensor signal voltage. The Vehicle Control Module (VCM) adjusts the fuel delivery based on the signal voltage. The Long and Short Term fuel values, which a scan tool can monitor, indicate a change made to the fuel delivery. Ideal Fuel Trim values are around 0 percent (128 counts). If the oxygen sensor signal indicates a lean condition, the VCM adds fuel. This results in fuel trim values above 0 percent . If the oxygen sensor detects a rich condition, the Fuel Trim values will read below 0 percent . This indicates that the VCM is reducing the amount of fuel delivered. The VCM sets this DTC when an excessively lean condition is detected.

CONDITIONS FOR RUNNING THE DTC

* No active O2 sensor DTCs
* No active TP sensor DTCs
* No active MAP sensor DTCs
* No active EGR sensor DTCs
* No active EVAP system sensor DTCs
* No active ECT sensor DTCs
* No active MAF sensor DTCs
* No active IAT sensor DTCs
* No active VS sensor DTCs
* No system voltage DTCs
* No active misfire DTCs
* The throttle position is less than 70 percent .
* The engine speed is between 575 and 4,000 RPM .
* The BARO is more than 70 kPa .
* The ECT is between 75 and 114°C (167-237°F) .
* The MAP is between 22 and 85 kPa .
* The IAT is between -8 and 76°C (46-169°F) .
* The MAF is between 3 and 85 g/s .
* The vehicle speed less than 85 mph .

CONDITIONS FOR SETTING THE DTC

The average of the Short Term Fuel Trim values over a period of 120 seconds indicates that a lean condition is present.

ACTION TAKEN WHEN THE DTC SETS

IMPORTANT: To complete a trip cycle for the fuel trim diagnostic, the Fuel Trim diagnostic test must enable and run according to the above enable criteria and the conditions for setting. A trip is not considered complete until the Fuel Trim diagnostic has run by the VCM.

When the current DTC initially sets, a software flag indicating an emissions related fault sets for 3 trips. The flag will clear provided the lean condition is no longer present. However, if the VCM detects the conditions for setting the current DTC during a trip while the flag is still set, the VCM turns on the Malfunction Indicator Lamp (MIL) . The MIL remains on during all of the subsequent trips until the DTC has been cleared by service or the lean condition has not been detected and the conditions for checking the fuel trim have been met for 3 consecutive trips.

CONDITIONS FOR CLEARING THE MIL OR DTC

* The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed.
* A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle.
* Use a scan tool in order to clear the DTCs.

DIAGNOSTIC AIDS

If using the diagnostic tables does not isolate the problem, try monitoring the Long Term FT and Fuel Trim cell while operating the vehicle under various loads. This may isolate the condition which caused the setting of the current DTC.

A condition that causes the DTC P0300 Engine Misfire Detected may also set the current DTC. Conversely an extremely lean condition which sets the current DTC can cause a misfire at idle and the DTC P0300 to set. If the cause of the current DTC cannot be determined and the DTC P0300 is also set, refer to DTC P0300 Engine Misfire Detected. See: P0300

Typical Fuel Trim Values



The fuel trim values table indicates the typical fuel adjustment values as displayed on a scan tool. Negative values, or a rich condition, indicates that the injector pulse width is being decreased in order to lean out the fuel mixture. Positive values, or a lean condition, indicates that the injector pulse width is being increased in order to richen the fuel mixture.

TEST DESCRIPTION

The numbers below refer to step numbers on the diagnostic table.

2. A more negative value indicates the VCM is leaning the fuel mixture or rich condition, and a more positive value indicates the VCM is richening the fuel mixture or a lean condition.

5. Visually and physically check the items that can cause a lean condition in order to determine the cause of the DTC being set.

Link: http://www.blazerforum.com/forum/showthread.php?t=35154

AA wrote:

Matthew, what does your engine do when you stop for a red light? Anything different than normal? Have you thrown any codes related to MAFF?

it runs a little rich when first started, and stumbles bad enough it stalls on occasion. When warmed up and after the car learns the trims its fine.
I had a P0102 code.
It's all fixed now and i've got my maf signal wire re-connected to the main engine connector.
It's a different problem that you guys are having, but i was just pointing out the the MAF doesnt seem to effect mileage all that much.

my car has brand new fuelpump, it has new fuel filter...and stayed in garage for 3 months(guess the fuel wont go so bad whit this time)
also i had injectors off and cleaned them.
inatek is cleaned/ sc is cleaned.

i buted the O rings between SC and intake.

i fixed the gasket problem between sc and throttle body whti that gasket maker what you sended rick.
and no its not leakign anymore. cooltant is allways in same lvl. also the car dos not have white smoke or anykind smoke.

it's stragne...cos it accelerates faster then ever before...burns tyres way easyer then before on accelarating..it did not have that much power before the repairs.
it's just not ideling good enaf.
i think it maybe have somekind vacum problem.
relly want to get silicone tubes but cant get them from here and shiping from usa woudl take 2weeks.
have to get the car in tiptop shape as fast as possible. got a long trip on 18dets.

il truy to take off the o2 sensor tomorrow...and check it. and maybe buy some ruber vacum lines.
it's a bit hard for me cos i cant get my car scanned easely, cant get the parts from here. all just takes time and is better to know exactly whats wrong.

did you check the vac line under the MAP sensor? It goes around to the side of the motor and plugs into the lower intake right under the snout.

Also, it take about 30 days for gas to spoil. Though i dont think your gas has gone bad enough to make the car throw a code.

Unfortunately, it's impossible to know exactly what is causing the problem.
You have to start somewhere using basic logic and rule out things one by one.
If you are still hearing a vacuum leak from the Brake Booster area, that is one big leak that needs to be fixed first. Then look at all the other hoses and replace with rubber or whatever you can get there. Forget about Silicone for now.
Check all the exhaust connections, at the cylinder heads, the crossover pipe, the down pipe, at the CAT. The smallest of leaks can cause this problem as well.
Keep looking and report back what you may have found.
I know you will find it.!!!!!

Anyone got any tips on testing the MAF??

Tank wrote:

Anyone got any tips on testing the MAF??

I am not sure how often MAF sensors go bad. If it is dirty or damaged, however, it will not work right, and if the wires to it are damaged (you already found problems in other wiring) its signal may not be correctly received. Why not check the wiring to the MAF first, for continuity. You should be able to check the wiring with a voltmeter.

I am not saying don't test the MAF, just saying that if you already found bum wires in the big connector at the firewall you might win by checking the wires to the MAF's connectors.

Do you suspect the car was in some sort of accident that is causing these wiring problems? Hopefully others who have had MAF problems (I have not) will comment, and hopefully you will post why you are now looking at the MAF for problems.

Albertj

A bad/dirty MAF sensor will show very extreme MAFF readings with a scanner. A wiring issue will throw a MAF sensor code, illuminating the SES lamp.

well we didn't find the bad wires in the firewall plug it was the inside plug. Should I check the firewall now? By the way..thats the plug right under that big vaccum box in the center right??

Well I didnt get to check my MAF wires yet. But when i started the car tonight it almost died..then on the way home cruising it just shut off! Then started up and ran normal. Could that be MAF problems?

Could be MAF, could also be vacuum leak. Take your MAF sensor out and sprat it with some electronic parts or MAF cleaner, just to be safe. I've done that before and it fixed a lean condition I had.

Could also be other things, crank/cam sensor, ignition module ground, etc.

Going through some wiring today:( Car runs but man it runs so sluggish and light keeps coming on everytime I start now.....oh what a night mare!! this car should run great after im done with all these repairs lol

That's good - find out what the code is and you will be a lot closer to your solution! Of course, getting codes read on a 95 is a bit of an issue in itself.

You've replaced all plugs and wires, right?

No I havent done that yet. I checked 4 of the plugs the other night...all I had time for. All those looked good.

If your car has more than 50k miles with the OEM wires, you may want to replace those (with new OEM wires) before suspecting anything else is wrong.

Ya not shur really lol. What do the OEM's look like?? Though it has 60k on the engine swap im for shur they are OEM lol But I keep getting MAF and TPS codes. Well unless the one's popping up this weekend were different but I will check that tommorow in class with the Genysis

I didn't know you had scanned - so the car is telling you it thinks the MAF and TPS are bad. Maybe replace TPS first; it's about $50.

Ya I am gonna start going through some more on Wednesday. I have a few cars to get done before I can get back to my own. I think I will go through some wiring too cause I had alot of bad wires in the ecm that got fixed. Does the MAF and TPS go through the firewall plug?? Maybe a dumb question but hey im learning here lol.

Quote :

I had alot of bad wires in the ecm that got fixed.

That bit of knowledge changes the perspective a bit. I'm going to guess there's nothing wrong with any of your sensors. What was the cause of the wire damage?

Corrosion. All wires in the plug inside the car to the ECM

Found some codes guy's here we go lol
PO101 MAF low
PO112-123 TPS high and low
PO172 Fuel trim Rich
PO321 Spark Refrence lost
P1361 ignition toggle malfunction

Well some updates on my MAF problems...I got Tonys MAF in the mail the other day and it worked fine for about an hour and then it died on and off. So today i was looking at the MAFF readings on the DHP while wiggling around the wires at the connector that goes into the sensor and I was getting all kind of flickering frequency values so it seems that the connector might be at fault here.

Opened up the pins in the connector to get better contact and its working again...cross your fingers boys. PS there was smoke coming from my rear manifold, a plug wire cover fell off and was melting on it  

Hello,
My '97 Riviera has been having some infrequent hesitations. Today, it had a big hesitation while accelerating and the Check Engine light came on. I had the error message scanned and it came out as "MAF or VAF A ckt low input".

Any idea on how to determine which is failing? (Also, I'm assuming the MAF sensor is by the throttle body and the VAF in the air cleaner box).

There is a 95 or 96 Riviera in my local junkyard. Would these sensors be the same as in 97?
Thank you.
Mikel

The scanner used to pull your code is reporting a generic code that covers "MAF or VAF", meaning in certain vehicles it could be called one or the other. Both sensors are used to measure volumes or density of the air coming into the engine. The sensor tells the computer (PCM) how much fuel to mix with the air for the best cylinder combustion. To my knowledge our cars use only MAF, not VAF. The sensor in the airbox is called the IAT sensor; it measures air temperature and will not likely trip the MAF/VAF code. The IAT sensor is likely fine, so ignore it for now.



The MAF sensor is a small flat, black plastic piece on top of the throttle body, right after the intake tube, held in by two safety torx screws. There are 3 things I would check right away:

1) Wiring to the sensor - plug, contacts, and wires should be clean and intact.
2) Sensor is clean - remove screws, shoot carefully with electronic parts cleaner until all residue is removed, and replace.
3) Sensor is intact - while removed, inspect sensor's fine wires are no damaged. It's like a light bulb. If the wires are broken, the sensor must be replaced.

The MAF sensors for Supercharged Series II engines are the same. These are shared from 96-99. Series II N/A engines use a different sensor for 95-97, and will not work in your car. Be careful handling the sensor, as it is delicate and expensive to replace. If you find yours is physically damaged, inspect the screen in the air intake, the intake tube, and air filter for cracks or leaks. No debris large enough to damage the MAF sensor should be getting past the filter and into the engine.

AA wrote:

The MAF sensors for Supercharged Series II engines are the same. These are shared from 96-99.

This is incorrect. The 96-98 cars use the same sensor, while the 99 and later model years are of a different design.