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 situated on the outside of the transmission, above the flywheel gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission above the flywheel ring gear, the G28 Engine Speed Sensor sends signals to ECU pin T55/49 via a grey wire. The ECU utilizes this information to regulate the amount of fuel and boost. It also sends an indication to the G5 tachometer inside the instrument cluster.
The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC, and where the camshaft lies so that it can activate the spark and injectors.
If this sensor fails when it fails, the ECU will display an error code P00160. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate an issue with the chain or a jump in the chain link of the upper chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).
It's a bit tricky to test as there are various pins on the connector and each has its own functions. The best way to do it is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms if the sensor is at full operation. If you are having problems with this sensor, look for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll, i experienced an abrupt drop in power as if the engine was running out of gas or injectors are not firing anymore. Today, i pulled out the spark plugs, three were drenched with gazoline the fourth was dry. I placed a tissue over each injector hole, and when i start the engine without sparks, the 3 with gazoline jump out. The 4th one stays closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found 0ohm. So i assume the problem is elsewhere.
I also tried to reset PID but without success. The car will start when the G28 is disconnected, but it is running fine with the G28 read more connected. However, the intermittent misfire problem continues to occur at higher RPM. The coolant sensor (G62) even when it is unplugged, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.
I don't know what to do. click here I believe that I've eliminated everything else. I'm concerned that i may have missed something. If anyone has any suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal sent website by the RPM sensor. The GM-style sensor is identical to the G4 and both are used in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a more info salvage yard or at a parts store. It is simple to test them - put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black end of the connector). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines requires to know both the speed and position of the crankshaft to determine timing of the fuel injector, etc. In order to do this it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these, the diagnostic scanner will display the codes that could trigger an engine website shutdown.
The signs of a malfunctioning G28 sensor include an inaccurate rev counter in the gearbox the gears are shifting faster than normal and/or misfiring when in gear. It is probable that your sensor is failing and requires to be replaced if you experience any of these signs. They're inexpensive and easy to locate, especially if they're a Bosch model like ours. You can also choose the GM version of this component is also a good choice.
5. Tachometer
A failing engine speed sensor could be a cause for a slew of issues in your vehicle. It's an essential component of your Audi's transmission, because it communicates to the ECU about how fast or slow the car's crankshaft is rotating. This sensor can cause the transmission to malfunction and other components in the car to be affected.
The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends a signal via gray wire to ECU pin T55/49. The ECU is then able to process the signal to control fuel, timig, and boost, and also sends it on to the G5 tachometer inside the instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. It should show approximately 1000 ohms resistance between these two points. This is a standard part across the Audi 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.