The 10 Scariest Things About Audi G28

How to Replace an audi car key case G28 Engine Speed Sensor

In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is situated on the edge of the transmission 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 situated on the edge of transmission, directly above the flywheel ring. The sensor transmits a signal via the grey wire to pin T55/49. The ECU then uses this information to control the boost, fuel, and timig. It also sends a signal to the G5 tachometer in the instrument cluster.

The sensor is used to link with the G40 Camshaft position Sensor. The ecu has to know when the crankshaft has reached TDC, and the position of the camshaft, to trigger the spark and injectors.

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

Testing can be a bit difficult because there are two connector pins, and they perform different functions however the best method of testing it is by measuring resistance between the sensor and the ECU. If the sensor is functional, it should read about 1000 ohms. Examine for evidence 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 a big cut in power as if the engine was running out of gas or the injectors aren't firing at all. I pulled out the spark plugs this morning and found that 3 were soaked with gasoline and the fourth was dry. When I crank the engine, there are no sparks i put tissue on the top of each of the injector holes, the 3 drenched with gazoline pop out, but the 4th stay closed. I checked the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I think the issue is somewhere else.

I also tried to reset PID without success. The car will start if the G28 is not plugged in and it runs perfectly when it is plugged in, but still has intermittent misfire issues at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of -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 crank up the engine.

I'm not sure what to do, as i feel i have pretty much ruled out everything else. I'm worried that i might have missed something. If anyone has any suggestions, please let me know! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style transmitter 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 salvage yard or from a parts store. Test them out - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's end). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that must know the position and speed of the crankshaft in order to make a decision about fuel injector timing etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go badly, you will see codes on the diagnostic scanner which could cause engine shut down.

A damaged G28 sensor could result in an inaccurate speed counter for your gearbox, a gearbox that shifts faster than normal, and/or a misfire in gear. It is probable that the sensor is failing and requires to be replaced if you encounter any of these signs. They're inexpensive and easy to locate especially in the case of a Bosch model like ours. Alternately, GM's version this part would be an option.

5. Tachometer

A malfunctioning engine sensor can cause a variety of issues in your vehicle. It is a crucial part of the audi car key replacement cost (Read More In this article)'s transmission because it communicates to the ECU about how fast or slow the car's crankshaft is rotating. When this sensor fails, it could affect the performance of the transmission and the rest of the car's components.

The G5 engine speed sensor is located at the outside of the transmission just above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49, via a grey wire. The ECU uses this signal to control the amount of fuel and boost, as well as timig. It also relays it to the G5 Tachometer located in the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should detect a resistance of approximately 1000 ohms between these points. This part is common across the audi q3 key 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du You may also find good ones in wrecking yards.