How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is situated at the edge of transmission just above the flywheel gear. It transmits a signal the ECU via an uncolored wire (T55/49) which is then sent to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends signals to ECU pin T55/49 via the grey wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an indicator to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft reached TDC and also the position of the camshaft, in order to activate the spark and injectors.
If this sensor fails the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync and could indicate the chain stretching or a jump link on the upper timing chain. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).
It is a little tricky to test because there are several connector pins, and they all have different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. When the sensor is operational, it should be reading around 1000 ohms. If you're having issues with this sensor, look for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at full speed I noticed a massive drop in power. It was as if the engine was running out of gas. Or, my injectors weren't firing. I pulled out the spark plugs this morning, three were soaked in gasoline, and the fourth was unclean. I put tissue over each injector hole and when i start the engine without sparks, the ones that have gazoline pop right out. The 4th one stays shut. I checked 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 PID but without success. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is 0.
I don't know what to do. I believe that I've eliminated everything else. I'm afraid i may have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal sent 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. It is easy to find the spare in a salvage shop or a parts store. Test them out by putting 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 how to open audi car key an ECU that must know the speed and position of the crankshaft to make a decision about timing of the fuel injector, for example. 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 badly, you will see codes on the diagnostic scanner which could cause engine shut down.
Some of the symptoms of a failed here G28 sensor include an inaccurate rev counter for the gearbox and gears that shift faster than normal, and/or a misfire when you're in gear. If you experience any of these issues, it is likely your sensor is failing and should be replaced. The good news is they are quite affordable and easily accessible particularly if you're looking at a Bosch unit which is what we have. Alternatively, GM's version of this part would be a good option.
5. Tachometer
A failing engine speed sensor could be a cause for many issues with your car. It is a crucial part of your Audi's transmission, since it audi key replacement near me relays information click here to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor could cause the transmission to malfunction and other components in the car to be affected.
The G5 engine speed sensor is located at the edge of the transmission just above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 through an uncolored wire. The ECU utilizes this signal to control the amount of fuel and boost, as well as timig. It also transmits it to the G5 Tachometer audi a4 spare key inside the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. You can also 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. It should show approximately 1000 ohms of resistance between those points. This part is common across the Audi 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 Du, so you might find good ones in wrecking yards.