How to Replace an audi q5 Key G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is located at the edge of transmission over the flywheel gear. It transmits a signal to the ECU via the grey wire (T55/49) and then to the tachometer in 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 a signal via the grey wire to pin T55/49. The ECU then uses this information to control the boost, fuel, and timig. It also sends signals to the G5 tachometer in the instrument cluster.
The sensor is used to audi connect key with the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors in the right way.
If this sensor fails, the ECU will display an error code P00160 which indicates that the Crank Shaft and Audi Q7 Replacement Key Intake Camshaft are out of sync, possibly indicating the chain stretching or a jump link on the upper timing chain. The code won't appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit challenging as there are two different pins for the connector and they perform different functions but the best method of testing it is to measure resistance between the sensor and the ECU. When the sensor is fully functional, it should read about 1000 ohms. If you're having issues with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at a high speed, i noticed a huge drop in power. It was like the engine was running out of gas. Or, my injectors weren't firing. In the morning, i removed the spark plugs, three were drenched in gazoline, the fourth was dry. When I start the engine with no sparks, I put a piece of tissue on the top of each of the injector holes and the 3 drenched with gazoline leap out, however the 4th stays shut. I tried to test the ground connections of ECU pins 14,30 and audi key blade 48/55. I found zero ohm. So i assume the problem is somewhere else.
I also tried to reset the PID but with no luck. The car is able to start if the G28 is disconnected and runs fine when it is plugged in, but still has intermittent misfire issues at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.
I'm not certain what to do, i feel i have pretty much ruled out everything else. I'm worried that i might have missed something. If anyone has any suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style transmitter is similar to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find a spare in a wrecking shop or a parts store. It is simple to test them: simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that has to know the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, for example. To do this, it uses 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 that could cause engine shut down.
A failing G28 sensor could cause an inaccurate speed counter for the gearbox and a gearbox which shifts faster than normal, or a misfire while in gear. If you have any of these issues it is likely your sensor is failing and should be replaced. The good news is they are very cheap and readily available, especially if you're looking at the Bosch sensor, which is what we have. Alternatively, GM's version of this part would be a good option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for many issues with your vehicle. It is an important part of the transmission in your audi key replacement cost since it sends information to the ECU regarding how fast or slow the car's engine is turning. This sensor could cause the transmission to fail and other car components to be affected.
The G5 engine speed sensor is located on the outside of the transmission above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 via an uncolored wire. The ECU is then able to process this signal to control the flow of fuel, timig and boost, and also transmitting it to the G5 tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Also, you can check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. There should be the resistance to be around 1000 ohms in these areas. This is a standard part that is found across the audi tt replacement key 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.