10 Mobile Apps That Are The Best For 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. This sensor is situated at the edge of transmission over the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer within 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 via a grey wire. The ECU utilizes this information to control boost and fuel. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors according to the situation.
If this sensor fails when it fails, the ECU will display a P00160 error message. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jump in the chain link of the upper timing chain. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).
It's a bit tricky to test because there are several pins on the connector and they all have different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. When the sensor is operational, it should read around 1000 ohms. If you're experiencing issues with this sensor, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at a high speed I noticed a significant decrease in power. It was like the engine was running out of gas. Or, my injectors were not firing. Today, i pulled out the spark plugs. Three were soaked with gazoline and the fourth one was dry. I put tissue over each injector hole and when I start the engine without sparks, the ones that have gazoline pop right out. The 4th one stays shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. My Web Site got 0ohm. Therefore, i think the issue is elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it runs fine with the G28 connected. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62) even when it is unplugged, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars but 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. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or 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 side up) and 2 (2nd from left on the black connector's side). They should be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines needs to be aware of the position and speed the crankshaft to determine fuel injector timing, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either one of these, the diagnostic scanner will display codes that could cause the engine shutting down.
A damaged G28 sensor could result in an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, and/or a misfire in gear. If you have any of these issues it is likely your sensor is failing and requires replacement. The good news is they are very cheap and easy to find particularly in the case of the Bosch unit which is what ours are. Alternatively, the GM version of this component is also a good choice.
5. Tachometer
A failing engine sensor could cause a myriad of issues within your vehicle. It's an essential component of the transmission in your Audi because it relays information to the ECU regarding how fast or slowly the engine is turning. This sensor could cause the transmission to fail and other components of the car to be affected.
The G5 engine speed sensor is situated on the outside of the transmission just above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 via a grey wire. The ECU is then able to process this signal to regulate fuel, timig, and boost as well as transmitting it to the G5 tachometer in the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe around 1000 ohms of resistance between those two pins. This is the same across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 DU So, you may find some good ones in wrecking yards.