How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is situated near the edges of the transmission above the flywheel ring gear. It transmits a signal the ECU via a grey wire (T55/49) and then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via a grey wire. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indicator to the G5 Tachometer in instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors according to the situation.
If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumpy chain link in the upper chain. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).
Testing is a bit tricky as there are two different connector pins, and they serve different purposes however the best method of testing it is to measure resistance between the sensor and the ECU. When the sensor is operational, it should read approximately 1000 ohms. If you're having issues with this sensor, look for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from 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, 3 were soaked in gasoline, and the fourth was dry. I placed a tissue over each injector hole, and when i start the engine with no sparks, the 3 that have gazoline pop right out. The 4th one remains closed. 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 elsewhere.
I also tried to reset PID without success. The car can start when the G28 is not check here plugged in and it runs perfectly when it is connected, but still has the intermittent misfire issue at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice temperature of -49c. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when I audi car key crank up the engine.
I don't know what to do. I believe that I've ruled everything else out. I'm concerned that i may have missed something. If anyone has any ideas please let me know! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. The GM-style sensor is identical to the G4 and both are used in the 80 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or at a parts store. Testing them is easy to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black end of the connector). check here 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 to make a decision about fuel injector timing etc. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor replacement car key audi (G28). If either of these sensors go badly, you will see codes on the diagnostic scanner that can lead to engine shutdown.
A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, or a misfire while in the gear. It is likely that the sensor is failing and needs to be replaced if you encounter any of these symptoms. The good thing is that they are quite affordable and readily available, especially in the case of a Bosch model, which is what ours are. Alternately, GM's version this part would be an option.
5. Tachometer
A failing engine speed here sensor could be the cause of numerous problems in your vehicle. It's an essential component of the transmission in your Audi because it relays information to the ECU on how fast or slowly the car's engine is spinning. This sensor can cause the transmission to malfunction and other components of the car to be affected.
The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel ring gear. It sends a signal to the ECU at pin T55/49 via a grey wire. The ECU uses this signal to control the flow of fuel and boost and also to timigrate. It also relays it to the G5 Tachometer in instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. It should show around 1000 ohms of resistance between those two pins. This is the same across the Audi 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 Du You may also find good ones in wrecking yards.