20 Myths About Audi G28: Busted
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 situated near the edges of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission, above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using an uncolored wire. The ECU utilizes this information to regulate boost and fuel. It also sends an alert to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. audi replacement key fob www.thekeylab.co.uk to be aware of when the crankshaft has reached TDC and also the position of the camshaft, in order to activate the spark and injectors.
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 code will not appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit challenging as there are two different pins for the connector and they perform different functions but the most effective method to test it is by measuring resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is at full operation. If you're experiencing issues with this part, check 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. I took out the spark plugs this morning and found that 3 were soaked with gasoline and the fourth was unclean. When I start the engine, there are no sparks, I put a piece of tissue on top of each injector hole and the 3 drenched with gazoline jump out but the 4th one stays closed. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 I get 0ohm. I think the issue is elsewhere.
I also tried to reset the PID without success. The car will start if the G28 is not plugged in and is running fine when it is plugged in however it is experiencing intermittent misfires at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows temperatures of -49c. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 when I crank up the engine.
I'm not sure what to do, as i believe that i've completely ruled out all other possibilities. I'm afraid i may have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style sender 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 wrecking yard or from a parts store. It is simple to test them - put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's end). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to know the speed and position of the crankshaft to make decisions regarding timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go bad you will get codes on the diagnostic scanner that could cause engine shut down.
Some of the signs of a failing G28 sensor include an inaccurate gearbox rev counter and gears that shift faster than normal and/or misfiring when in gear. If you experience any of these issues it is most likely that your sensor is deteriorating and should be replaced. The good news is that they are very affordable and easy to find particularly in the case of the Bosch unit which is what ours are. Alternatively, the GM version of this part is also a good choice.
5. Tachometer
A faulty engine speed sensor could be a cause for numerous issues with your car. It's a vital component of your Audi's transmission, since it relays information to the ECU about how fast or slow the car's crankshaft is rotating. If this sensor fails, it can disrupt the performance of the transmission and the other car's components.
The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It transmits an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU then processes this signal to regulate fuel, timig, and boost and then sends it on 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 ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. It should show around 1000 ohms of resistance between those points. This is the same across the Audi 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 Du So, you may find good ones in wrecking yards.