How to Replace an Audi G28 Engine Speed Sensor
In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is situated near the edges of the transmission above the flywheel ring gear. It sends a signal to the ECU via a grey wire (T55/49), then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, just above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends signals to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC, and the position of the camshaft, in order to activate the spark and injectors.
If this sensor fails to function, the ECU will display a P00160 error code. This indicates that the Crank Shaft is not in sync with the Intake Camshaft. It could also be a sign of an issue with the chain or a jumpy chain link in the upper chain of timing. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).
Testing is a bit challenging as there are two different pins for the connector and they serve different purposes however the best method of testing it is to measure the resistance between the sensor and the ECU. It should read around 1000 ohms if the sensor is operating at its maximum. Examine for signs of coolant, or oil in the connector bay if you have issues with this component.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll i had an abrupt drop in power like the engine is out of gas or injectors aren't firing any more. I pulled out the spark plugs this morning, three were drenched in gasoline and the fourth was dry. I placed a tissue over each injector hole and when I start the engine without sparks, the three with gazoline jump out. The 4th one stays closed. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 I got 0ohm. I think the issue is in another location.
I also tried to reset the PID what is the audi advanced key but with no luck. The car will start when the G28 is disconnected, but it runs fine with the G28 connected. However the intermittent misfire issue persists at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value -49c even when i unplug it. I also advanced key audi noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 when i rev the engine.
I'm not sure what to do, as i think i've pretty much ruled out everything else. However, i'm afraid that I might have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal from the RPM sensor. get more info The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or a parts store. Testing them is easy to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's end). They replacement car key audi must be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that must know the position and speed of the crankshaft in order to make a decision about fuel injector timing etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes badly, you will see codes on the diagnostic scanner that could cause engine shut down.
The signs of a failed G28 sensor are an inaccurate rev counter in the gearbox the gears are shifting faster than normal, and/or a misfire when you're in gear. If you have any of these problems, it is likely that your sensor is going bad and should be replaced. They're inexpensive and easy to locate especially if they're a Bosch unit like ours. Alternately, GM's version this part would be a good option.
5. Tachometer
A faulty engine speed sensor could be a cause for many issues with your car. It is an important part of the transmission of your Audi since it sends information to the ECU about how fast or slowly the engine is turning. 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 edge of the transmission, over the flywheel ring. It sends a signal via gray wire to ECU pin T55/49. The ECU then uses and processes this signal to control fuel, timig and boost as well as sends it on to the G5 tachometer in the instrument cluster. You can check the sensor for failure by examining the continuity between it and the tachometer, between the ECU get more info pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see approximately 1000 ohms of resistance between those points. This part is common across the Audi 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 DU So, you may find some good ones in wrecking yards.