Why Nobody Cares About Audi G28

How to Replace an audi key fob not working G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is located on the edge of the transmission above the flywheel ring gear. It transmits a signal to the ECU through the grey wire T55/49 and replacement key for audi then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

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

The sensor serves as a reference point to connect 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 trigger spark and injectors according to the situation.

If this sensor fails the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and could indicate chain stretch or a jumped link on the upper timing chain. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).

It's a bit tricky to test since there are various connector pins, and they all have different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. If the sensor is functional, it should read about 1000 ohms. If you're experiencing issues with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at maximum speed, i noticed a huge drop in power. It was as if the engine was running out of gas. Or my injectors were not firing. I took out the spark plugs this morning, 3 were drenched in gasoline and the fourth was dry. I put tissue over each hole in the injector and when I start the engine with no sparks, the 3 with gazoline jump out. The 4th one stays closed. I tested the ground connection of ECU pins 14,30, and 48/55. I found zero ohm. I'm assuming the issue is somewhere else.

I also tried to reset the PID but with no luck. The car will start when the G28 is unplugged, and it is running fine with the G28 plugged in. However the intermittent misfire issue persists at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.

I'm not sure what to do, as i think i've pretty much eliminated everything else. I'm afraid i may have missed something. If anyone has any ideas please chime in! TIA!

3. Fuel Pump

The fuel pump of the g28 receives signals from the RPM sensor. The GM-style sensor is the same as the G4 and they both work in the 80 100 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or from a parts store. It is easy to test them - simply put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). 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 to make decisions about timing of the fuel injectors, etc. In order to do this it makes use of 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 which could cause engine shut down.

A damaged G28 sensor could result in an inaccurate speed counter for the gearbox or a gearbox that shifts more quickly than normal, or an unfire when in the gear. It is possible that your sensor is failing and needs to be replaced if you notice any of these symptoms. They are cheap and easy-to-find particularly if they're an Bosch sensor like ours. Alternately, the GM version of this unit is also a good option.

5. Tachometer

A malfunctioning engine speed sensor could be a cause for a slew of issues in your vehicle. It is an important part of the transmission in your audi car key replacement cost, as it transmits information to the ECU regarding how fast or slowly the engine is turning. This sensor can cause the transmission to fail and other car components to be affected.

The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel ring gear and sends a signal directly 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 sends it to the G5 Tachometer in instrument cluster. You can test the sensor for failure by checking continuity between it and audi a4 replacement key (https://appc.cctvdgrw.com) the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. It should show approximately 1000 ohms of resistance between those points. This part is common across the audi tt replacement key 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU So, you may find good ones in wrecking yards.