7 Simple Changes That Will Make A Big Difference With Your 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. more resources is situated near the edges of the transmission above the flywheel ring gear. It sends a message to the ECU through the grey wire T55/49 and then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission, above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 using a grey wire. The ECU uses this information to regulate boost and fuel. It also sends an indicator to the G5 Tachometer located in the instrument cluster.

The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft has reached TDC, and the position of the camshaft, so that it can activate the spark and injectors.

If this sensor fails to function, the ECU will display an error code P00160. This means that the Crank Shaft is out of sync with the Intake Camshaft. It could also be a sign of an issue with the chain or a jumpy chain link in the upper chain of timing. The code won't show without the additional information supplied by other sensors (G4 or G40).

Testing can be a bit difficult because there are two pins for the connector and they perform different functions but the best method of testing it is to measure the resistance between the sensor and the ECU. It should read about 1000 ohms when the sensor is operating at its maximum. Check for evidence of coolant or oil in the connector bay if you have issues with this part.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced massive power loss like the engine is running out of gas or injectors aren't firing anymore. Today, i pulled out the spark plugs, three were drenched with gazoline the fourth one was dry. I put a piece of tissue over each hole in the injector and when I start the engine without sparks, the ones that have gazoline pop right out. The 4th one stays closed. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. I assume that the problem is somewhere else.

I also tried to reset the PID with no success. The car is able to start when the G28 is disconnected and it runs perfectly when it is plugged in, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when it is unplugged, shows an ice 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, i think i've pretty much eliminated everything else. I'm afraid i may have missed something. If anyone has any ideas please let me know! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra in a wrecking shop or parts store. It is easy to test them - simply switch 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 should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines needs to be aware of the speed and position of the crankshaft to make decisions regarding timing of fuel injectors, etc. It makes use of 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 which could cause engine shut down.

Some of the signs of a failing G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or misfiring when you're in gear. If you have any of these issues, it is most likely that your sensor is going bad and requires replacement. The good thing is that they are very cheap and easy to find, especially if you're looking at the Bosch model, like ours. Alternatively, GM's version of this part would be an option.

5. Tachometer

A faulty engine speed sensor could be the cause of many problems in your car. It is a crucial part of the Audi's transmission because it communicates to the ECU about how the car's crankshaft is spinning. This sensor can cause the transmission to malfunction and other components of the car to be affected.

The G5 engine speed sensor is located at the outside 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 utilizes this signal to regulate fuel and boost, and also to timigrate. It also transmits it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, 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 and pin T26a/12. You should detect an average resistance of 1000 ohms in these areas. This is a common part that is found across the Audi 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.

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Pub: 17 Mar 2024 22:20 UTC
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