How to Replace an Audi G28 Engine Speed Sensor

In this video Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located near the transmission's edge just above the flywheel gear. It transmits a signal to the ECU via an uncolored wire T55/49, then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated at the edges of the 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 the amount of fuel and boost. It also sends a signal to the G5 Tachometer located in the instrument cluster.

The sensor is used to connect with the G40 Camshaft position Sensor. The ecu has to know when the crankshaft has reached TDC, and audi tt key case the position of the camshaft, so that it can activate the spark and injectors.

If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also indicate a chain stretch or a jumped chain link in the upper chain. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).

It can be a bit difficult to test as there are various pins on the connector, and each has its own functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. If the sensor is operational, it should be reading about 1000 ohms. If you're experiencing issues with this sensor, look for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll, i experienced a big cut in power like the engine is out of gas or injectors aren't firing at all. I pulled out the spark plugs this morning and found that 3 were soaked in gasoline, and the fourth was dry. When i crank the engine without sparks, I put a piece of tissue on top of each injector hole, the 3 drenched with gazoline pop out, but the 4th one stays shut. I tried to test the ground connections 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 the PID but with no luck. The car can start when the G28 is disconnected and runs fine when it is connected, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows temperatures of -49c. Also i noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 when I crank up the engine.

I don't know what to do. I think I've eliminated everything else. But i am afraid I may have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal 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. You can easily locate a spare in a wrecking shop or parts store. It is simple to test them - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to be aware of the position and speed of the crankshaft to determine timing of the fuel injector, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you have a problem with either one of these, the diagnostic scanner will display codes that could lead to an engine shutdown.

The signs of a failed G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal and/or a misfire when in gear. If you are experiencing any of these issues it is most likely that your sensor is deteriorating and needs replacing. They're cheap and easy to find, Audi Tt Key Case especially when they're a Bosch model like ours. If you prefer, GM's version of this component is an option.

5. Tachometer

A damaged engine sensor could cause a number of problems within your vehicle. It's a vital component of the Audi Tt Key Case's transmission since it relays information to the ECU about how fast or slow the car's crankshaft is rotating. When this sensor fails, it could disrupt the performance of the transmission, as well as the other car's components.

The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU then uses and processes this signal to control fuel, timig and boost, and also sends it on to the G5 tachometer in the instrument cluster. You can test the sensor replacement key for audi any failure by checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. There should be the resistance to be around 1000 ohms in these areas. This is a standard part across the Audi 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.