How to Replace an audi key fob replacement cost G28 Engine Speed Sensor

Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is located on the edge of the transmission just above the flywheel ring gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

The grey wire is located at the edges of the transmission, directly above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer in instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can activate spark and injectors accordingly.

If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync and could indicate chain stretch or a jumped link on the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).

It is a little tricky to test because there are several pins on the connector, and they all have different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. When the sensor is fully operational, it should read approximately 1000 ohms. Examine for signs of coolant, or oil in the connector bay if you have issues with this part.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, I experienced massive power loss like the engine is out of gas or injectors are not firing anymore. This morning i pull out the spark plugs, three were soaked with gazoline and the fourth was dry. When I crank the engine with no sparks i put tissue on top of each injector hole and the 3 drenched with gazoline leap out, however the 4th stay shut. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got zero ohm. I'm assuming that the issue is in another location.

I also tried to reset PID but without success. The car is able to start when the G28 is not plugged in and runs fine when it is connected however it is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c even when i unplug it. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do, as i feel i have pretty much completely ruled out all other possibilities. But i am afraid i might have missed something. If anyone has any suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal from the RPM sensor. The GM-style transmitter is the same as the G4 and they both work in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or from a parts store. Testing them is easy to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black end of the connector). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to know the position and speed of the crankshaft in order to make decisions regarding timing of the fuel injectors, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these sensors, the diagnostic scanner will show codes that could cause an engine shut down.

A malfunctioning G28 sensor can cause an inaccurate speed counter for the gearbox, a gearbox that shifts more quickly than normal, or an unfire when in gear. If you have any of these issues it is likely your sensor is deteriorating and requires replacement key audi. They're inexpensive and easy to locate, especially when they're a Bosch model like ours. Alternatively, the GM version of this unit is also a good option.

5. Tachometer

A damaged engine sensor could cause a number of problems in your car. It is an important part of the transmission in your audi car key case (supplemental resources), as it transmits information to the ECU on how fast or slow the engine is turning. This sensor can cause the transmission to malfunction and other components in the car to be affected.

The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU then processes this signal to regulate fuel, timig and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Also, you can check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 as well as pin T26a/12. You should detect an average resistance of 1000 ohms between these two points. This is a typical part across the audi q3 key 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.