How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is situated on the outside of the transmission just above the flywheel gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission, above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through an uncolored wire. The ECU then utilizes this information to regulate fuel, timig and boost. spare audi key sends an indication to the G5 tachometer inside the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu has to be aware of when the crankshaft has reached TDC, and where the camshaft lies in order to activate 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 an issue with the chain or a jump in the chain link of the upper chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).
audi a1 keys 's a bit tricky to test since there are various pins on the connector and each has its own 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 be reading about 1000 ohms. If you're experiencing issues with this sensor, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced a big cut in power like the engine is running out of gas or the injectors aren't firing any more. This morning i pull out the spark plugs. Three were drenched with gazoline the fourth one was dry. When i crank the engine without sparks i put tissue on the top of each of the injector holes and the 3 that were drenched in gazoline jump out but the 4th one stays closed. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. I'm assuming that the issue is in another location.
I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However, the intermittent misfire problem still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of that is -49c even after unplugging it. I also noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 if i crank up the engine.
I'm not certain what to do, but i think i've pretty much ruled out everything else. I'm afraid i may have missed something. If anyone has any ideas please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or parts store. audi a1 key replacement is easy to test them - simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that must know the position and speed of the crankshaft in order to make a decision about 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 either of these goes wrong, you will receive codes on the diagnostic scanner which could cause engine shut down.
Some of the signs of a failing G28 sensor include an inaccurate rev counter in the gearbox the gears are shifting faster than normal, and/or a misfire when you are in gear. If you are experiencing any of these problems, it is likely your sensor is deteriorating and should be replaced. The good news is that they are very affordable and easy to find, especially in the case of the Bosch sensor, which is what we have. Alternatively, GM's version of this part is a good option.
5. Tachometer
A malfunctioning engine sensor can cause a number of problems in your vehicle. It's an essential component of the transmission of your Audi because it relays information to the ECU regarding how fast or slow the engine is turning. When this sensor fails, it will disrupt the performance of the transmission and the rest of the car's components.
The G5 engine sensor is located at the edge of transmission, above the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to regulate the amount of fuel and boost, and also to timigrate. It also transmits it to the G5 Tachometer located in the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. There should be a resistance of approximately 1000 ohms in these areas. This is a standard part across the Audi 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.