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. This sensor is located on the outside of the transmission over the flywheel gear. It sends a message to the ECU through an uncolored wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via the grey wire. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indication to the G5 tachometer in the instrument cluster.

The sensor is used to connect the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can activate spark and injectors according to the situation.

If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating chain stretch or a jumped link on the upper chain of timing. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).

Testing can be a bit difficult since there are two connector pins, and they serve different purposes however the best way to test it is to measure resistance between the sensor and the ECU. When the sensor is fully operational, it should be reading around 1000 ohms. If you are having problems with this component, look for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, while accelerating from the highway paytoll at full speed, i noticed a huge decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs. Three were drenched with gazoline the 4th one was dry. When i crank the engine, there are no sparks, i place a tissue on the top of each of the injector holes, the 3 drenched with gazoline jump out but the 4th stay closed. I tested the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. So i assume the problem is somewhere else.

I also tried to reset PID but without success. The car will start when the G28 is disconnected and it runs perfectly when it is connected however it has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when it is unplugged, shows an ice temperature of -49c. I also noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 when i click here rev the engine.

I don't know what to do. I feel like i've pretty much all other possibilities out. I'm concerned that i may have missed something. If anyone has suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style sensor is identical to 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 salvage yard or in a local parts store. It is easy to test them - just put your DMM into resistance mode and determine the distance between pins read more 1 and 2 (with the bump on the connector's edge facing up). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that has to be aware of the speed and position of the crankshaft to make a decision about fuel injector audi spare key replacement timing etc. read more It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you encounter a problem with either of these, the diagnostic scanner will display codes that could cause the engine audi car key shutting down.

The signs of a failing G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal and/or misfiring when you're in gear. If you are experiencing any of these issues, it is most likely that your sensor is deteriorating and should be replaced. The good thing is that they are very affordable and readily available particularly in the case of the Bosch model, like ours. Alternately, the GM version of this part is also a good choice.

5. Tachometer

A faulty engine speed sensor could be the reason behind numerous issues in your vehicle. It's a vital component of your Audi's transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is rotating. If this sensor fails, it can disrupt the performance of the transmission, as well as the rest of the car's components.

The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate the amount of fuel and boost, and also timig. It also transmits it to the G5 Tachometer located in the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. Also, you can examine the continuity between pins 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 the resistance to be around 1000 ohms between these points. This is a common feature across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS An and 1995 RS2 Du So, you may find good ones in wrecking yards.