How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is located at the top of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the outside of the transmission, directly above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU then uses this information to control the boost, fuel, and timig. It also sends a signal to the G5 Tachometer located in the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC, and the location of the camshaft in order to activate the spark and injectors.
If this sensor fails, the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper timing chain. The code won't show without the additional information provided 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 in full operation. Check for evidence of coolant or oil in the connector bay if there are issues with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced massive power loss as if the engine was running out of gas or the injectors are not firing any more. This morning i pull out the spark plugs, three were soaked with gazoline and the fourth one was dry. I put tissue over each injector hole and when i start the engine without sparks, the three with gazoline jump out. The fourth one remains closed. I checked the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. I assume that the problem is in another location.
I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it runs fine with the G28 connected. However the intermittent misfire issue still occurs at higher RPM. The coolant sensor (G62) even when unplugged, still shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.
I'm not sure what to do. I feel like i've pretty much all other possibilities audi spare key out. I'm afraid i may have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal from the RPM sensor. click here The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or a parts store. Test them out to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black end of the connector). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that has to know the speed and position of the crankshaft to make decisions about fuel injector timing etc. It makes use of a Crank Position Sensor G4 and an here Engine Speed Sensor G28 to achieve this. If either of these go wrong, you will receive codes on the diagnostic scanner which can lead to engine shutdown.
A damaged G28 sensor could cause an inaccurate speed counter for your gearbox, a gearbox that shifts more quickly than normal, and/or an unfire when in the gear. If you experience any of these issues, it is likely your sensor is failing here and needs replacing. They are cheap and easy-to-find particularly in the case of an Bosch unit like ours. Alternatively, GM's version of this component is a good option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for numerous problems in your car. It is a crucial part of your Audi's transmission, since it relays information to the ECU about how fast or slow the car's crankshaft is rotating. audi keys replacement This sensor could cause the transmission to malfunction and other components of the car to be affected.
The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It transmits signals via an uncolored wire to the ECU pin T55/49. The ECU is then able to process this signal to control fuel, timig, and boost, and also sends it on to the G5 tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, 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. There should be the resistance to be around 1000 ohms between these points. This is a common feature across the Audi 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 DU, so you might find them in wrecking yards.