Why Audi G28 Doesn't Matter To Anyone
Why Audi G28 Doesn't Matter To Anyone
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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 located at the top of the transmission, above the flywheel ring gear. It sends a message to the ECU through an uncolored wire T55/49, then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, directly above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU utilizes this information to control boost and fuel. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft has reached TDC and also where the camshaft lies in order to activate the spark and injectors.
If this sensor fails the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating the chain is stretched or a jump link on the upper timing chain. The code won't appear without the additional information supplied by other sensors (G4 or G40).
It can be a bit difficult to test because there are different pins on the connector and they all have different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. When the sensor is fully operational, it should read about 1000 ohms. Check for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced a big cut in power like the engine is running out of gas or the injectors aren't firing at all. This morning i pull out the spark plugs, three were drenched in gazoline, the fourth one was dry. I put a piece of tissue over each injector hole and when i start the engine with no sparks, the three that have gazoline pop right out. The 4th one remains shut. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 I get zero Ohm. I'm assuming that the issue is in another location.
I also tried to reset the PID without success. The car will start when the G28 is disconnected and it runs perfectly when it is click here connected, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. Also i 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 certain what to do, but i feel i have pretty much eliminated everything else. I'm afraid i may have missed something. read more If anyone has suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter is identical to the G4 read more and both function in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a audi a1 key wrecking yard or from a parts store. It is easy to test them - just put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that has to be aware of the speed and position of the crankshaft to make decisions regarding timing of the fuel injectors, etc. In order to do this it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these sensors, the diagnostic scanner will display the codes that could trigger an engine shutdown.
A failing G28 sensor could result in an inaccurate speed counter for your gearbox and a gearbox which shifts more quickly than normal, and/or a misfire while in gear. If you are experiencing any of these problems, it is likely that your sensor is going bad and should be replaced. The good news is that they are very cheap and readily available, especially when you're looking at the Bosch sensor, which is what ours are. Alternatively, the GM version of this unit is also a good choice.
5. Tachometer
A faulty engine speed sensor could be the reason behind a slew of issues with your car. It is a crucial part of the Audi's transmission since it relays information to the ECU about how the car's crankshaft is spinning. If this sensor fails, it can disrupt the performance of the transmission, as well as the rest of the car's components.
The G5 engine speed sensor is located at the outside of the transmission above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 via a grey wire. The ECU then processes this signal to regulate fuel, timig, and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can check for sensor failure by examining the continuity of 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 [79trace [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 website common feature across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU, so you might find good ones in wrecking yards.