How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is located on the edge of the transmission, above the flywheel ring gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, just above the flywheel ring. The sensor transmits a signal via the grey wire to pin T55/49. The ECU then uses this information to control fuel, timig and boost. It also sends an alert to the G5 Tachometer within the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors in the right way.
If this sensor fails, the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync and could indicate the chain is stretched or a jump link on the upper timing chain. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).
It is a little tricky to test since there are various pins on the connector and they all have different functions. The best way to do it is to measure the resistance between the ECU and the sensor. If the sensor is operational, it should read approximately 1000 ohms. If you're experiencing issues with this sensor, look for signs of oil or coolant in the connector bay.
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 the injectors aren't firing any more. Today, i pulled out the spark plugs. Three were drenched with gazoline the fourth was dry. When i crank the engine, there are no sparks, i place a tissue on the top of each of the injector holes and the 3 drenched with gazoline jump out but the 4th stays shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got zero ohm. I think the issue is in another location.
I also tried to reset the PID but without success. The car is able to start if the G28 is unplugged and is running fine when it is plugged in however it has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. I also 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 certain what to do, i believe that i've eliminated everything else. But Visit Homepage am afraid I might have missed something. If anyone has any ideas please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 gets 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 an extra in a wrecking shop or 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 the left on the black connector's end). They should be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that must know the speed and position of the crankshaft to make decisions regarding timing of the fuel injectors, etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes bad you will get codes on the diagnostic scanner which can lead to engine shutdown.
Some of the symptoms of a failing G28 sensor include an inaccurate rev counter in the gearbox and gears that shift faster than normal, and/or a misfire when in gear. If you experience any of these issues, it is likely your sensor is failing and needs replacing. The good news is they are very cheap and easily accessible particularly when you're looking at the Bosch sensor, which is what ours are. Alternatively, GM's version of this component is a good option.
5. Tachometer
A failing engine sensor could cause a variety of issues in your vehicle. It's an essential component of your Audi's transmission, because it communicates to the ECU about how fast or slow the vehicle's crankshaft is rotating. how to get a new audi key could cause the transmission to fail and other components of the car to be affected.
The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It sends a signal via an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to regulate the flow of fuel and boost and also to timigrate. It also sends it to the G5 Tachometer inside the instrument cluster. You can determine if the sensor is in failure by checking continuity from the sensor to the tachometer. You can also examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 as well as pin T26a/12. You should see approximately 1000 ohms resistance between those two pins. This is a standard part across the Audi 80 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best ones could be available in wrecking yards.