Why You Should Forget About Improving Your Audi G28

How to Replace an audi car key holder G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is located at the edge of transmission over the flywheel gear. It transmits a signal the ECU via the grey wire (T55/49) and then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

The grey wire is located on the edge of transmission, above the flywheel ring. This 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 is used to connect with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft reached TDC, and the position of the camshaft, to trigger the spark and injectors.

If this sensor fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of sync with the Intake Camshaft. It could also indicate a chain stretch or a jumpy chain link in the upper timing chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).

Testing is a bit tricky as there are two different connector pins and they serve different purposes however the best method of testing it is by measuring resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is operating at its maximum. If you are having problems with this part, check for evidence of coolant or oil in the connector bay.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, i experienced an abrupt drop in power like the engine is running out of gas or the injectors are not firing at all. I took out the spark plugs this morning, 3 were soaked 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 stays shut. I checked the ground connection of ECU pins 14,30 and 48/55. I found zero ohm. So i assume the problem is elsewhere.

I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However the intermittent misfire issue still occurs at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is zero.

I don't know what to do. I believe that I've all other possibilities out. But i am afraid I might have missed something. If anyone has any suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal sent by the RPM sensor. The GM-style sensor 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 salvage yard or in a local parts store. It is simple to test them - just put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that needs to know the speed and position of the crankshaft to make decisions about timing of the fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you encounter a problem with either of these sensors, the diagnostic scanner will show codes that could cause an engine shut down.

A malfunctioning G28 sensor can cause an inaccurate gearbox speed counter, a gearbox that shifts faster than normal, or a misfire in gear. If you are experiencing any of these issues it is likely your sensor is failing and needs replacing. They're inexpensive and easy to locate, especially in the case of a Bosch sensor like ours. You can also choose the GM version of this unit is also a good option.

5. Tachometer

A malfunctioning engine speed sensor could be the cause of numerous issues in your vehicle. It's a vital component of your programming audi key's transmission, since it relays information to the ECU about how fast or slow the vehicle's crankshaft is spinning. If the sensor audi spare key cost 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, over the flywheel ring. It transmits an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to regulate the amount of fuel and boost, and also to timigrate. It also relays it to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by checking continuity from 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 as well as pin T26a/12. There should be a resistance of approximately 1000 ohms between these points. This is a common feature across the audi tt key case 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du You may also find them in wrecking yards.