What The Heck What Is Audi G28?

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. The sensor is located at the top of the transmission above the flywheel ring gear. It transmits a signal to the ECU via an uncolored wire (T55/49) and then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using the grey wire. The ECU utilizes this information to regulate fuel and boost. It also sends an indicator to the G5 Tachometer in instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware of when the crankshaft has reached TDC and also 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 sync with the Intake Camshaft. It could also indicate a chain stretch or a jumped chain link in the upper timing chain. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).

Testing can be a bit difficult because there are two pins for the connector and they have different functions but the best way to test it is by measuring resistance between the sensor and the ECU. It should read about 1000 ohms when it is at full operation. If you're having issues with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, when accelerating from highway paytoll at a high speed, i noticed a huge reduction in power. It was like the engine was running out of gas. Or my injectors weren't firing. I took out the spark plugs this morning, 3 were soaked in gasoline, and the 4th was dry. I put tissue over each injector hole, and when i start the engine with no sparks, the 3 with gazoline jump out. The 4th one remains closed. I tested the ground connection of ECU pins 14,30, and 48/55. I found zero ohm. I'm assuming the issue is elsewhere.

I also tried to reset PID but without success. The car will start if the G28 is not plugged in and it runs perfectly here when it is connected, but still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when unplugged, still shows temperatures of -49c. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas 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. However, i'm afraid that I might have missed something. If anyone has any suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump in the get more info g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra in a wrecking shop or parts store. Testing them is easy by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black end of the connector). They should be infinite ohms.

4. ECU

Our read more 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that must be aware of the speed and position of the crankshaft in order to make a decision about timing of the get more info fuel injectors, etc. 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 here diagnostic scanner that could cause engine shut down.

The signs of a failed G28 sensor include an inaccurate rev counter for the gearbox and gears that shift faster than normal, and/or a misfire when in gear. It is possible that the sensor is failing and requires to be replaced if you experience any of these symptoms. They are cheap and easy-to-find particularly in the case of an Bosch unit like ours. If you prefer, GM's version of this component is an excellent choice.

5. Tachometer

A failing engine sensor could cause a number of problems in your car. It's a vital component of the Audi's transmission since it relays information to the ECU about how fast or slow the car's crankshaft is spinning. If the sensor fails, it will cause problems for the transmission, as well as the other car's components.

The G5 engine speed sensor is located on the edge of the transmission above the flywheel ring gear and sends a signal to the ECU at pin T55/49 via a grey wire. The ECU uses this signal to control fuel and boost, and also timig. It also transmits it to the G5 Tachometer inside the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect an average resistance of 1000 ohms between these points. This is the same across the Audi 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU So, you may find good ones in wrecking yards.