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. The sensor is located at the edge of transmission over the flywheel gear. It sends a signal to the ECU via an uncolored wire (T55/49), then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the outside of the transmission, above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU then uses this information to control the boost, fuel, and timig. It also sends an indication to the G5 Tachometer located in 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 also the position of the camshaft, in order to activate the spark and injectors.
If this sensor fails the ECU will throw an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are not in sync, possibly indicating the chain stretching or a jump link on the upper chain of timing. The code won't show without the additional information supplied by other sensors (G4 or G40).
Testing is a bit challenging because there are two connector pins and they serve different purposes but the most effective method to test it is to measure the resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is at full operation. Look for signs of coolant or oil in the connector bay if there are problems with this part.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed I noticed a massive reduction in power. It was like the engine had run out of gas. Or my injectors were not firing. In the morning, i removed the spark plugs, 3 were soaked with gazoline and the fourth one was dry. I put a piece of tissue over each injector hole and when I turn the engine on without sparks, the three that have gazoline pop right out. The fourth one remains closed. I tested the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I'm assuming the issue is more info elsewhere.
I also tried to reset the PID but without success. The car is able to start when the G28 is disconnected and it runs perfectly when it is connected, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62) even when it is unplugged, shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is 0.
I'm not sure what to do. I believe that I've all other possibilities out. However, i'm afraid that i might have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style sensor is the same as the G4 and both function in the 80 100 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or from a parts store. It is easy to test them - simply switch 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 have an ECU that must know the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, for example. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you have a problem with either of these sensors, the diagnostic scanner will show codes that could cause an engine shutdown.
Some of the signs of a failing G28 sensor include an inaccurate gearbox rev counter and gears that shift faster than normal and/or a misfire when you're in gear. If you are experiencing any of these problems, it is likely your sensor is deteriorating and requires replacement. They are cheap and easy-to-find particularly if they're an Bosch model like ours. get more info Alternatively, the GM version of this unit is also a good option.
5. Tachometer
A failing engine speed sensor could be the cause of numerous problems in your vehicle. It is an important part of the transmission of your Audi since it sends information to the ECU on how fast or slow the car's engine is spinning. This sensor can cause the transmission to malfunction and other car components to be affected.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It transmits an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU read more uses this check here signal to control fuel and boost, and also timig. It also relays it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity from the sensor to the tachometer. You can also verify continuity between pin T55/49 of the ECU and pin T6a/1 click here of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. There should be a resistance of approximately 1000 ohms in these areas. This is a standard 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 might be availble in wrecking yards.