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. This sensor is located at the edge of transmission just above the flywheel gear. It transmits a signal the ECU via the grey wire (T55/49), then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU utilizes this information to regulate boost and fuel. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu has to know when the crankshaft has reached TDC, and the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync and could indicate chain stretch or a jumped link on the upper timing chain. 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 as there are several pins on the connector, and each one has different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. If genuine audi key replacement uk is operational, it should be reading about 1000 ohms. If you are having problems with this part, check for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at full speed, i noticed a huge reduction in power. It was as if the engine was running out of gas. Or my injectors weren't firing. This morning i pull out the spark plugs. Three were soaked with gazoline and the fourth one was dry. I placed a tissue over each hole in the injector and when I turn the engine on without sparks, the three with gazoline jump out. The fourth one remains shut. I checked the ground connection of ECU pins 14,30, and 48/55. I found zero ohm. I'm assuming the issue is elsewhere.
I also tried to reset the PID but with no luck. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However, the intermittent misfire problem continues to occur at higher RPM. The coolant sensor (G62), even when unplugged, still shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.
I don't know what to do. I feel like i've pretty much all other possibilities out. I'm worried that i might have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal from the RPM sensor. The GM-style sensor is the same as the G4 and both are used in the 80 100, 200, UrS and RS2 cars so you can easily find one at a junkyard or at a parts store. Click At this website is simple to test them by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's side). They must be infinite ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that must be aware of the speed and position of the crankshaft in order to make decisions 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 goes wrong, you will receive codes on the diagnostic scanner that can lead to engine shutdown.
Some of the symptoms of a failed G28 sensor are an inaccurate rev counter for the gearbox, gears shifting quicker than normal, and/or a misfire when you are in gear. If you experience any of these issues it is likely that your sensor is failing and requires replacement. The good thing is that they are quite affordable and readily available, especially if you're looking at the Bosch sensor, like ours. Alternately, the GM version of this unit is also a good option.
5. Tachometer
A malfunctioning engine speed sensor could be the cause of numerous issues with your vehicle. It is a crucial part of the Audi's transmission since it relays information to the ECU about how fast or slow the car's crankshaft is turning. If the sensor fails, it could cause problems for the transmission, as well as the rest of the car's components.
The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It transmits a signal via gray wire to ECU pin T55/49. The ECU utilizes this signal to control the amount of fuel and boost, and also timig. It also transmits it to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. There should be an average resistance of 1000 ohms in these areas. This is a typical part across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best ones could be available in wrecking yards.