Audi G28: The Good, The Bad, And The Ugly
Audi G28: The Good, The Bad, And The Ugly
Blog Article
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you 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 message to the ECU through the grey wire T55/49 and then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via the grey wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used 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 activate spark and injectors accordingly.
If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is out of alignment with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumped chain link in the upper chain. The code won't show without the additional information supplied by other sensors (G4 or G40).
It can be a bit difficult to test as there are various pins on the connector, and each one has different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. When the sensor is fully operational, it should read around 1000 ohms. If you're having issues with this sensor, look for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at full speed, i noticed a huge decrease in power. It was like the engine had run out of gas. Or, my injectors were not firing. Today, i pulled out the spark plugs, 3 were soaked with gazoline and the fourth one was dry. When i crank the engine without sparks i put tissue on the top of each hole in the injector and the 3 drenched with gazoline leap out, however the 4th stay shut. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 I got 0ohm. I'm assuming that the issue is somewhere else.
I audi a1 key replacement also tried to reset PID but without success. The car will start when the G28 is unplugged, and it works fine when the G28 connected. However, the intermittent misfire problem continues to occur at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is 0.
I'm not sure what to do. I feel like i've pretty much ruled everything else out. I'm concerned that i may have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find an extra in a wrecking shop or a parts store. Testing them is easy - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's side). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines must know the speed and position of the crankshaft to determine timing of the fuel injector, etc. To accomplish this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these, the diagnostic scanner will display codes that could cause an engine shut down.
Some of the symptoms of a failing G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or a misfire when you are in gear. If you are experiencing any of these issues, it is most likely that your sensor is deteriorating and should be replaced. They're cheap and easy to find especially when they're a Bosch unit like ours. Alternatively, the GM version of this part is also a good option.
5. Tachometer
A malfunctioning engine sensor can cause a variety of issues in your vehicle. It is a crucial part of the Audi's transmission since it relays information to the ECU about how more info the car's crankshaft is turning. When this sensor fails, it will cause problems for the transmission, as well as the other car's components.
The G5 engine speed sensor is located on the outside of the transmission above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49, via a grey wire. The ECU then processes this signal to control fuel, timig and boost, and also sends it on to the G5 tachometer in the instrument cluster. You can check for sensor failure by get more info checking continuity from the sensor to the tachometer. You can also examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 as well as pin T26a/12. You should see around 1000 ohms of resistance between those two pins. This is a common part that is found across the Audi 80, 100, 200, UrS and RS2 range from more info 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones might be audi a1 keys availble in wrecking yards.