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. The sensor is situated near the edges of the transmission, above the flywheel ring gear. It transmits a signal the ECU via the 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 G28 Engine Speed Sensor sends a signal to ECU pin T55/49 using the grey wire. The ECU utilizes this information to control fuel and boost. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used to link the G40 Camshaft position Sensor. The ecu has to be aware of when the crankshaft has reached TDC and also the position of the camshaft, in order to activate the spark and injectors.
If this sensor fails when it fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumped chain link in the upper chain. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).
Testing is a bit tricky since there are two connector pins, and they serve different purposes but the most effective method to test it is to measure resistance between the sensor and the ECU. It should read about 1000 ohms when it is at full operation. If you are having problems with this sensor, look for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced massive power loss like the engine is running out of gas or injectors are not firing anymore. This morning i pull out the spark plugs, three were soaked with gazoline and the fourth one was dry. When I start the engine without sparks, I put a piece of tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th stays closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got zero ohm. Therefore, i think the issue is elsewhere.
I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.
I don't know what to do. I think I've all other possibilities out. But i am afraid I might have missed something. If anyone has any suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or parts store. It is easy to test them - simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines must know the position and speed of the crankshaft in order to make a decision about timing of the fuel injector, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you have a problem with either of these, the diagnostic scanner will show codes that could cause an engine shutdown.
Some of the signs of a failing G28 sensor are an inaccurate rev counter in the gearbox the gears are shifting faster than normal and/or misfiring when you're in gear. If you experience any of these problems, it is likely your sensor is failing and requires replacement. They're inexpensive and easy to locate, especially if they're an Bosch sensor like ours. Alternately, the GM version of this component is also a great option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for many issues in your car. It's an essential component of the Audi's transmission as it sends information to the ECU about how fast or slow the car's crankshaft is turning. Visit Webpage could cause the transmission to malfunction and other components of the car to be affected.
The G5 engine sensor is located at the edge of transmission, above the flywheel ring. It transmits signals via a gray wire to the ECU pin T55/49. The ECU is then able to process the signal to control fuel, timig and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can test for sensor failure by examining the continuity from the sensor to the tachometer. Also, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 as well as pin T26a/12. You should see the resistance to be around 1000 ohms in these areas. This is the same across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 Du So, you may find them in wrecking yards.