Audi G28: The Good, The Bad, And The Ugly
Audi G28: The Good, The Bad, And The Ugly
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How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located at the top of the transmission, above the flywheel ring gear. It transmits a signal the ECU via the grey wire (T55/49) and then to the tachometer located in 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 using an uncolored wire. The ECU uses this information to control fuel and boost. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used to connect with the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors accordingly.
If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is out of sync with the Intake Camshaft. It could also indicate a chain stretch or a jumpy chain link in the upper timing chain. However the code will not appear on its own without additional information from other sensors (G4 and G40).
It's a bit tricky to test as there are several pins on the connector and each one has different functions. The best way to do it is to measure the resistance between the ECU and the sensor. When the sensor is functional, it should read approximately 1000 ohms. If you're having issues with this part, check for signs of coolant or oil 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 running out of gas or the injectors are not firing anymore. This morning i pull out the spark plugs. Three were drenched with gazoline the 4th one was dry. I put tissue over each injector hole and when i start the engine with no sparks, the ones with gazoline jump out. The fourth one remains closed. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. I get 0ohm. So i assume the problem is in another place.
I also tried to reset PID without success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However the intermittent misfire issue continues to occur audi a1 key at higher RPM. The temperature sensor for the 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 bars while the actual pressure is 0.
I'm not sure what to do, as i believe that i've eliminated everything else. I'm afraid i may have missed something. Please let me know should you have any suggestions! get more info TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra in a wrecking shop or parts store. It is simple to test them - just put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They must be audi car key replacement infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that needs to know the position and speed of the crankshaft to make a decision about timing of the fuel injector, for example. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these sensors, the diagnostic scanner will show codes that could lead to an engine shutdown.
The signs of a malfunctioning G28 sensor are an inaccurate rev counter for the gearbox and gears that shift faster than normal and/or a misfire when you are in gear. It is possible that the sensor is failing and needs to be replaced if you experience any of these symptoms. They're cheap and easy to find especially when they're a Bosch unit like ours. Alternatively, the GM version of this unit is also a good option.
5. Tachometer
A malfunctioning engine speed sensor could be the cause of a slew of issues with your audi convenience key vehicle. It's a vital component of the Audi's transmission since it relays information to the ECU about how the car's crankshaft is rotating. If the sensor fails, it could cause problems for the transmission and the other car's components.
The G5 engine speed sensor is situated on the outside of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49, audi key replacement near me via a grey wire. The ECU then processes this signal to regulate fuel, timig and boost, and also transmitting it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by 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 [79]), and between pin T6a/1 and pin T26a/12. It should show approximately 1000 ohms of resistance between those two pins. This is a common part across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.