How to Replace an audi replacement car keys G28 Engine Speed Sensor

In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is situated near the transmission's edge, above the flywheel gear. It transmits a signal to the ECU via the grey wire T55/49 and then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the edge of transmission, directly above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU utilizes this information to regulate boost and fuel. It also sends an indicator to the G5 Tachometer located in the instrument cluster.

The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors in the right way.

If this sensor fails the ECU will display the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync and could indicate chain stretch or a jumped link on the upper chain of timing. However, the error 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 connector pins, and each one has different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. When the sensor is fully functional, audi tt key replacement it should read about 1000 ohms. Check for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at maximum speed, i noticed a huge drop in power. It was like the engine had run out of gas. Or, my injectors weren't firing. I pulled out the spark plugs this morning and found that 3 were drenched in gasoline and the 4th was dry. When I crank the engine with no sparks, I put a piece of tissue on top of each injector hole and the 3 drenched with gazoline jump out but the 4th stay closed. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. I'm assuming that the issue is somewhere else.

I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62), even when it is unplugged, shows temperatures of -49c. Also i noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do, but i believe that i've eliminated everything else. But i am afraid i might have missed something. If anyone has suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is identical to the G4 and both function in the 80 100 200, UrS and RS2 cars so you can easily find one at a junkyard or in a local parts store. It is easy to test them - just switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They should 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. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go bad you will get codes on the diagnostic scanner that can lead to engine shutdown.

Some of the symptoms of a malfunctioning G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal, and/or a misfire when in gear. It is likely that the sensor is failing and needs to be replaced if you encounter any of these symptoms. The good news is that they are very affordable and easily accessible particularly if you're looking at the Bosch sensor, which is what we have. If you prefer, GM's version of this part is an excellent choice.

5. Tachometer

A faulty engine speed sensor could be a cause for numerous issues with your vehicle. It is a crucial part of the audi tt replacement key's transmission because it communicates to the ECU about how fast or slow the car's crankshaft is turning. This sensor can cause the transmission to fail and other components of the car to be affected.

The G5 engine speed sensor is situated on the outside of the transmission above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through an uncolored wire. The ECU then processes the signal to control fuel, timig and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can check 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 [79trace [79]), and between pin T6a/1 as well as pin T26a/12. You should see around 1000 ohms of resistance between these two points. This part is common across the audi tt key replacement 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 DU, so you might find some good ones in wrecking yards.