How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located at the edge of transmission just above the flywheel gear. It transmits a signal the ECU via an uncolored 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 a signal to ECU pin T55/49 using the grey wire. The ECU utilizes this information to control the amount of fuel and boost. It also sends signals to the G5 Tachometer located in the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and the location of the camshaft so it can activate spark and injectors in the right way.
If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of a chain stretch or a jump in the chain link of the upper chain. The code won't show without the additional information supplied by other sensors (G4 or G40).
It's a bit tricky to test because there are different pins on the connector, and each one has different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. It should read approximately 1000 ohms when the sensor is at full operation. If you're experiencing issues with this part, check 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 injectors aren't firing at all. I took out the spark plugs this morning, three were soaked with gasoline and the fourth was unclean. When I start the engine, there are no sparks, I put a piece of tissue on the top of each of the injector holes and the 3 drenched with gazoline jump out but the 4th stay closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got zero ohm. please click the next internet page assume that the problem is in another location.
I also tried to reset the PID with no success. The car is able to start if the G28 is disconnected and is running fine when it is plugged in, but still is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of -49c even when i unplug it. Also i noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 when I crank up the engine.
I don't know what to do. I think I've all other possibilities out. I'm afraid i may have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 receives 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 salvage yard or at a parts store. It is easy to test them - simply switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines requires to know the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, etc. To do this, it makes use of 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 can cause the engine to shut down.
A damaged G28 sensor can cause an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, or a misfire in gear. It is likely that your sensor is failing and needs to be replaced if you experience any of these signs. The good news is that they are very affordable and easy to find, especially in the case of an Bosch model, which is what we have. Alternately, GM's version this part would be an option.
5. Tachometer
A faulty engine speed sensor could be a cause for numerous problems in your vehicle. It's a crucial component of the transmission of your Audi because it relays information to the ECU regarding how fast or slowly the engine of the car is turning. This sensor could 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, over the flywheel ring. It sends signals via a gray wire to the ECU pin T55/49. The ECU uses this signal to control fuel and boost, as well as timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can test the sensor for failure by examining 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. You should see an average resistance of 1000 ohms between these points. This is a common component across the Audi 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.