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 on the edge of the transmission just above the flywheel ring gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, just above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU uses this information to control the amount of fuel and boost. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used to connect with the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC, and where the camshaft lies so that it can activate the spark and injectors.
If this sensor fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of sync 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. The code will not appear without the additional information supplied by other sensors (G4 or G40).
It is a little tricky to test because there are several pins on the connector, and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is at full operation. Check for evidence of coolant or oil in the connector bay if you are experiencing issues with this component.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, i experienced an abrupt drop in power as if the engine was running out of gas or injectors are not firing anymore. I took out the spark plugs this morning and found that 3 were soaked in gasoline, and the fourth was dry. I placed a tissue over each injector hole and when I start the engine without sparks, the ones with gazoline jump out. The 4th one remains shut. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. i get zero Ohm. I'm assuming that the issue is elsewhere.
I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it runs fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is 0.
I'm not certain what to do, but i think i've pretty much eliminated everything else. I'm worried that i might have missed something. Let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate the spare in a salvage shop or parts store. It is simple to test them 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
The ECU in our 20vt turbo (3B AAN ABY) engines must know both the position and speed of the crankshaft in order to make a decision about timing of the fuel injector, etc. In order to do this it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes here badly, you will see codes on the diagnostic scanner which could cause engine shut down.
A failing G28 sensor could result in an inaccurate gearbox speed counter or a gearbox that shifts more quickly than normal, and/or a misfire in gear. It is probable that your sensor is failing and needs to be more info replaced if you encounter any of these signs. They're inexpensive and easy to locate especially if they're a Bosch sensor like ours. Alternately, GM's version this part would be a good option.
5. Tachometer
A damaged engine sensor could cause a myriad of issues in your vehicle. It is a crucial part of your Audi's transmission, because it communicates to the ECU about how fast or slow the vehicle's crankshaft is spinning. If click here the sensor fails, it will disrupt the performance of the transmission and the rest of the car's components.
The G5 engine speed sensor is situated on the edge of the transmission, above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU is then able to process this signal to regulate the flow of fuel, timig and boost, and also sends it on to the G5 tachometer in the instrument cluster. You can check the sensor for failure by get more info 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]) as well as between T6a/1, and the instrument cluster pin read more T26a/12. It should show approximately 1000 ohms resistance between those two pins. This is a typical part that is found across the Audi 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.