10 Things You Learned From Kindergarden They'll Help You Understand Audi G28

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 on the edge of the transmission just above the flywheel ring gear. It transmits a signal the ECU via a grey wire (T55/49) and then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is located at the edges of the transmission, just above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends an alert to the G5 Tachometer in instrument cluster.

The sensor is used to link with the G40 Camshaft position Sensor. The ecu must know when the crankshaft reached TDC and also the position of the camshaft, to trigger the spark and injectors.

If this sensor fails the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are not in sync and could indicate the chain stretching or a jump link on the upper chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).

It is a little tricky to test because there are several pins on the connector and each has its own functions. The best way to do it is to measure the resistance between the ECU and the sensor. When the sensor is fully operational, it should be reading about 1000 ohms. If you're having issues with this part, check for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, while accelerating from the highway paytoll at maximum speed I noticed a significant drop in power. It was like the engine had run out of gas. Or my injectors weren't firing. This morning i pull out the spark plugs, 3 were drenched in gazoline, the 4th one was dry. I put tissue over each hole in the injector and when i start the engine with no sparks, the 3 that have gazoline pop right out. The 4th one remains closed. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 I got zero ohm. I'm assuming the issue is in another place.

spare audi key cost G28 Car Keys UK tried to reset the PID but without success. The car can start when the G28 is unplugged and runs fine when it is plugged in, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62) even when unplugged, still shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.

I'm not certain what to do, as i think i've pretty much ruled out everything else. However, i'm afraid that I may have missed something. If anyone has suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump in the g28 receives signals from the RPM sensor. The GM-style transmitter is the same as the G4 and they both work in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a salvage yard or at a parts store. Test them out to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's side). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that must know the position and speed of the crankshaft in order to make a decision about fuel injector timing etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these sensors go badly, you will see codes on the diagnostic scanner that can cause the engine to shut down.

Some of the symptoms of a failed G28 sensor include an inaccurate gearbox rev counter the gears are shifting faster than normal and/or a misfire when in gear. If you have any of these problems, it is likely that your sensor is going bad and needs replacing. They're inexpensive and easy to locate particularly when they're a Bosch unit like ours. Alternately, the GM version of this unit is also a good option.

5. Tachometer

A malfunctioning engine sensor can cause a variety of issues within your vehicle. It's an essential component of the Audi's transmission since it relays information to the ECU about how fast or slow the car's crankshaft is spinning. This sensor can cause the transmission to malfunction and other components in the car to be affected.

The G5 engine speed sensor is situated on the outside of the transmission just above the flywheel ring gear and sends a signal to the ECU at pin T55/49, via an uncolored wire. The ECU uses this signal to control the amount of fuel and boost, and also timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe approximately 1000 ohms of resistance between those two pins. This is a common feature across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and 1995 RS2 Du, so you might find them in wrecking yards.

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Pub: 01 Oct 2024 22:35 UTC
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