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 near the transmission's edge, above the flywheel gear. It sends a message to the ECU via the grey wire T55/49 and then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission, above the flywheel ring gear the G28 Engine Speed Sensor sends signals to ECU pin T55/49 using the grey wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an indication to the G5 Tachometer within the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC and also the position of the camshaft, to trigger the spark and injectors.
If this sensor fails the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain stretching or a jump link on the upper timing chain. The code won't show without the additional information supplied by other sensors (G4 or G40).
Testing is a bit tricky since there are two connector pins and they perform different functions but the best method to test it is by measuring resistance between the sensor and the ECU. It should read about 1000 ohms when it is in full operation. If you're having issues with this component, look for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at full speed I noticed a significant drop in power. It was like the engine was running out of gas. Or, my injectors weren't firing. This morning i pull out the spark plugs. Three were soaked with gazoline and the 4th one was dry. When I start the engine without sparks, i place a tissue on top of each injector hole, the 3 drenched with gazoline jump out but the 4th stay closed. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. Therefore, i think the issue is somewhere else.
I also tried to reset the PID but without success. The car is able to start if the G28 is not plugged in and runs fine when it is plugged in, but still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows an ice temperature of -49c. Also i noticed that the oil pressure gauge in the cockpit is showing check here 2 bar while the actual pressure is 0.0 if i crank up the engine.
I don't know what to do. I feel like i've pretty much all other possibilities out. I'm concerned that i may have missed something. If anyone has suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style sender is the same as the G4 and both are used in the 80 100, 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or in a local parts store. It is simple to test them - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that has to know the position and speed of the crankshaft in order 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 (G28). If you are experiencing issues with either of these, the diagnostic scanner will display codes that could cause an engine shut down.
A malfunctioning G28 sensor could cause an inaccurate gearbox speed counter, a gearbox that shifts faster than normal, and/or an unfire when in gear. It is probable that the sensor is failing and requires to be replaced if you encounter any of these signs. The good thing is that they are very affordable and readily available particularly in the case of an Bosch sensor, which is what we have. Alternatively, the GM version of this part is also a good choice.
5. Tachometer
A malfunctioning engine speed sensor could be the cause of a slew of issues with your car. It's an essential component of the Audi's transmission more info because it communicates to the ECU about how fast or slow the car's crankshaft is turning. When this sensor fails, it will affect the performance of the transmission and the other car's components.
The G5 engine speed sensor is located at the edge of the transmission just above the flywheel ring gear. It sends a signal to the ECU at pin T55/49, via a grey wire. The ECU then uses and processes the signal to control the flow of fuel, timig and boost and then sends it on to click here the G5 tachometer inside the instrument cluster. You can test the sensor for any failure read more by checking the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection via pin audi a4 car key replacement T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see around 1000 ohms of resistance between those two pins. This is a standard component across the Audi 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.