10 Untrue Answers To Common Audi G28 Questions: Do You Know The Right Ones?
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 on the outside of the transmission, above the flywheel gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer in the instrument cluster.
1. audi key replacement cost The Keylab is situated on the outside of the transmission, above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU uses this information to regulate the amount of fuel and boost. It also sends an indicator to the G5 Tachometer in instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft has reached TDC and also where the camshaft lies to trigger 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 and could indicate chain stretch or a jumped link on the upper chain of timing. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).
It can be a bit difficult to test because there are several connector pins, and they all have different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. If the sensor is functional, it should read around 1000 ohms. If you are having problems with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced an abrupt drop in power like the engine is out of gas or the injectors are not firing any more. I pulled out the spark plugs this morning and found that 3 were drenched in gasoline and the 4th was dry. When I crank the engine without sparks, I put a piece of tissue on the top of each of the injector holes and the 3 drenched with gazoline jump out but the 4th stay shut. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero ohm. I think the issue is elsewhere.
I also tried to reset PID but without success. The car can start when the G28 is unplugged and runs fine when it is connected however it has the intermittent misfire issue at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows a temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do. I believe that I've all other possibilities out. But i am afraid I may have missed something. Please let me know if you have any ideas! 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 works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or parts store. Testing them is easy by putting your DMM in resistance mode and measure the resistance 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
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to know the speed and position of the crankshaft in order to make a decision about fuel injector timing etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get 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 the gears are shifting faster than normal and/or misfiring when you are in gear. If you have any of these issues, it is likely that your sensor is going bad and needs replacing. The good news is they are quite affordable and easy to find particularly if you're looking at a Bosch model, like ours. You can also choose the GM version of this unit is also a good choice.
5. Tachometer
A damaged engine sensor could cause a number of problems in your car. It's a vital component of your Audi's transmission, since it relays information to the ECU about how the car's crankshaft is spinning. If the sensor fails, it can affect the performance of the transmission, as well as the other car's components.
The G5 engine speed sensor is located on the edge of the transmission just above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 via an uncolored wire. The ECU is then able to process this signal to regulate fuel, timig, and boost, and also sends it on to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. Also, 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 see around 1000 ohms of resistance between those points. This is a common feature across the Audi 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU So, you may find some good ones in wrecking yards.