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 located at the top of the transmission just above the flywheel ring gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, directly above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU uses this information to regulate fuel and boost. It also sends a signal to the G5 tachometer inside the instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must 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 show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating the chain is stretched or a jump link on 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 connector pins and they have different functions however the best method of testing it is by measuring resistance between the sensor and the ECU. When the sensor is operational, it should read about 1000 ohms. If you are having problems with this component, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced a big cut in power like the engine is running out of gas or the injectors aren't firing at all. I pulled out the spark plugs this morning, three were drenched in gasoline and the fourth was unclean. I put tissue over each hole in the injector and when I start the engine without sparks, the three with gazoline jump right out. The 4th one remains closed. I tested the ground connection of ECU pins 14,30, and 48/55. I found zero ohm. Therefore, i think the issue is in another place.
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 still occurs at higher RPM. The coolant sensor (G62), even when it is unplugged, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is zero.
I'm not certain what to do, but i think i've pretty much ruled out everything else. I'm concerned that i may have missed something. If anyone has suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily find an extra in a wrecking shop or a parts store. Test them out - 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 should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines needs to know both the position and speed of the crankshaft to make audi replacement car keys decisions regarding timing of the fuel injector, etc. To do this, it makes use of 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 can cause the engine to shut down.
A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, or a misfire in the gear. It is probable that your sensor is failing and requires here to be replaced if you experience any of these signs. They are cheap and easy-to-find especially in the case of a Bosch sensor like ours. Alternatively, GM's version of this part would be an excellent choice.
5. Tachometer
A car key replacement audi malfunctioning engine sensor can cause a variety of issues within your vehicle. It's a crucial component of the transmission in your Audi since it sends information to the ECU regarding how fast or slowly the engine is turning. This sensor could cause the transmission to fail and other components of the car to be affected.
The G5 engine sensor is located near the edge of the transmission, just above click here the flywheel ring. It sends signals via a gray wire to the ECU pin T55/49. The ECU uses this signal to control fuel and boost, as well as timig. It also transmits it to the G5 Tachometer inside the instrument cluster. You can check for sensor failure by checking continuity from the sensor to the tachometer. You can also check 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 replace audi key see around 1000 ohms of resistance between those two pins. This is a common feature across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 DU You may also find some good ones in wrecking yards.