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 situated at the top of the transmission above the flywheel ring gear. It sends a message to the ECU via an uncolored wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission above the flywheel ring gear, the G28 Engine Speed Sensor sends signals to ECU pin T55/49 via a grey wire. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft has reached TDC, and the position of the camshaft, to trigger the spark and injectors.
If this sensor fails, the ECU will display an error code P00160. This means that the Crank Shaft is not in alignment 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. However the code will not appear on its own without additional information from other sensors (G4 and G40).
It's a bit tricky to test since there are various pins on the connector and each one has different functions. The best way to do it is to measure the resistance between the ECU and the sensor. When the sensor
Audi Q7 Key is fully operational, it should read about 1000 ohms. Examine for signs of coolant or oil in the connector bay if you are experiencing problems with this part.
2. Injectors
Yesterday, while accelerating from the highway paytoll at full speed, i noticed a huge drop in power. It was like the engine had run out of gas. Or, my injectors were not firing. Today, i pulled out the spark plugs, three were drenched in gazoline, the 4th one was dry. I put tissue over each injector hole, and when I start the engine with no sparks, the 3 that have gazoline pop right out. The 4th one remains closed. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. I think the issue is elsewhere.
I also tried to reset the PID but with no luck. The car can start when the G28 is not plugged in and is running fine when it is plugged in but it still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. Also, i noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.
I don't know what to do. I think I've all other possibilities out. But i'm worried that I may have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style sensor is identical to the G4 and both are used in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or in a local 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 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 must know the position and speed of the crankshaft to make decisions about timing of the fuel injector, for example. To accomplish this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go wrong, you will receive codes on the diagnostic scanner which could cause engine shut down.
Some of the signs of a failing G28 sensor include an inaccurate gearbox rev counter, gears shifting quicker than normal and/or a misfire when in gear. It is probable that the sensor is failing and needs to be replaced if you notice any of these signs. They are cheap and easy-to-find especially if they're an Bosch model like ours. Alternately,
Audi q7 key the GM version of this component is also a good option.
5. Tachometer
A malfunctioning engine speed sensor could be the cause of many issues with your vehicle. It is an important part of the transmission in your
Audi Q7 Key because it relays information to the ECU regarding how fast or slow the engine of the car is spinning. If this sensor fails, it can cause problems for the transmission and the rest of the car's components.
The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU then processes the signal to control fuel, timig, and boost and then sends it on to the G5 tachometer inside the instrument cluster. You can check for sensor failure by examining the continuity
cost of audi key replacement 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 and pin T26a/12. You should observe around 1000 ohms of resistance between these two points. This is a typical part across the
new audi keys 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.