Audi G28: The Ugly The Truth About Audi G28
Audi G28: The Ugly The Truth About Audi G28
Blog Article
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is situated at the top of the transmission above the flywheel ring gear. It sends a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer in 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 signals to ECU pin T55/49 via a grey wire. The ECU utilizes this information to control the amount of fuel and boost. It also sends a signal to the G5 tachometer inside the instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft reached TDC, and the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails to function, the ECU will display a P00160 error message. This indicates that the Crank Shaft is not in line with the Intake Camshaft. It could also indicate a chain stretch or a jumped chain link in the upper chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).
It can be a bit difficult to test as there are several pins on the connector and each has its own functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms if the sensor is in full operation. Check for signs of coolant or oil in the connector bay if there are issues with this component.
2. Injectors
Yesterday, when accelerating from highway paytoll at a high speed I noticed a significant decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. In the morning, i removed the spark plugs, 3 were drenched in gazoline, the fourth was dry. When I start the engine without sparks i put tissue on the top of each hole in the injector and the 3 that were drenched in gazoline leap out, however the 4th stays shut. I tried to test the ground connections 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 more info the PID here without success. The car will start if the G28 is not plugged in and runs fine when it is plugged in, but still is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of -49c even when i unplug it. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar when the actual pressure is 0.0 when i rev the engine.
I'm not sure what to do. I believe that I've all other possibilities out. But i'm worried that I might have missed something. Let me know If you have any suggestions! TIA!
3. Fuel Pump
The get more info fuel pump on the g28 is activated by a signal from the RPM sensor. The GM-style sender is the same as the G4 and both are used in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a junkyard or in a local parts store. Testing them is easy - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's end). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines needs to know both the position and speed the crankshaft to make decisions regarding timing of the fuel injector, etc. It uses a Crank Position more info Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you are experiencing issues with either of these sensors, the diagnostic scanner will show codes that could cause an engine shutdown.
The signs of a failed G28 sensor include an inaccurate rev counter in the gearbox the gears are shifting faster than normal and/or misfiring when you're in gear. If you have any of these issues it is likely your sensor is going bad and should be replaced. They are cheap and easy-to-find, especially when they're a Bosch model like ours. Alternately, GM's version this component is a good option.
5. Tachometer
A damaged engine sensor could cause a variety of issues within your vehicle. It's a vital component of your Audi's transmission, because it communicates to the ECU about how fast or slow the car's crankshaft is rotating. When this sensor fails, it could disrupt the performance of the transmission, as well as the other car's components.
The G5 engine speed sensor is located at the outside of the transmission just above the flywheel ring gear and sends a signal to the ECU at pin T55/49, via a grey wire. The ECU is then able to process the signal to control fuel, timig, and boost and then transmitting it to the G5 tachometer inside the instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, you can check continuity between pin T55/49 of the ECU and pin T6a/1 check here of the instrument cluster (trace [79]), and between pin T6a/1 as well as pin T26a/12. You should detect a resistance of approximately 1000 ohms between these points. This is a common feature across the Audi 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 Du, so you might find them in wrecking yards.