How to Replace an Audi car key holder G28 Engine Speed Sensor

Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is situated near the edges of the transmission just above the flywheel ring gear. It sends a signal to the ECU via a grey wire (T55/49) and then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

The grey wire is located on the edge of transmission, above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an indicator to the G5 Tachometer in instrument cluster.

The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC, and the location of the camshaft to trigger the spark and injectors.

If this sensor fails to function, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of sync with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumpy chain link in the upper chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).

Testing is a bit tricky because there are two connector pins, and they serve different purposes but the most effective way to test it is to measure the resistance between the sensor and the ECU. When the sensor is fully operational, it should be reading about 1000 ohms. If you're having issues with this sensor, look for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll i had an abrupt drop in power like the engine is running out of gas or the injectors are not firing anymore. I took out the spark plugs this morning, three were drenched in gasoline and the fourth was dry. When I start the engine, there are no sparks i put tissue on the top of each hole in the injector and the 3 drenched with gazoline pop out, but the 4th stays closed. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero Ohm. I think the issue is elsewhere.

I also tried to reset the PID without success. The car will start if the G28 is not plugged in and runs fine when it is connected however it has the intermittent misfire issue at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.

I'm not sure what to do. I believe that I've ruled everything else out. But i'm worried that i might have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style sensor is identical to the G4 and both function in the 80, 100 200, UrS and RS2 cars so you can easily find one at a wrecking yard or in a local parts store. It is simple to test them - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's side). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that needs to be aware of the speed and position of the crankshaft to make decisions regarding timing of the fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these sensors go wrong, you will receive codes on the diagnostic scanner that can cause the engine to shut down.

Some of the symptoms of a failing G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or a misfire when you're in gear. If you are experiencing any of these issues it is most likely that your sensor is failing and should be replaced. The good news is they are quite affordable and readily available, especially if you're looking at a Bosch model, which is what ours are. Alternatively, GM's version of this part is an option.

5. Tachometer

A failing engine speed sensor could be the cause of a slew of issues in your audi car keys. It's an essential component of the transmission of your replacement audi key cost, as it transmits information to the ECU about how fast or slow the engine is spinning. This sensor could cause the transmission to fail and other car components to be affected.

The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU then uses and processes the signal to control fuel, timig and boost and then sends it on to the G5 tachometer inside the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. You can also 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 a resistance of approximately 1000 ohms between these points. This is a common component across the audi replacement key 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.