The Most Pervasive Issues In Audi G28
The Most Pervasive Issues In Audi G28
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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 situated near the edges of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via the grey wire T55/49 and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the outside of the transmission, just above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends an indication to the G5 tachometer inside the instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can activate spark and injectors in the right way.
If this sensor fails the ECU will throw an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating chain stretch or a jumped link on the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
Testing is a bit tricky as there are two different connector pins, and they have different functions but the best way to test it is by measuring resistance between the sensor and the ECU. When the sensor is operational, it should be reading about 1000 ohms. Check for signs of coolant or oil in the connector bay if you have problems with this part.
2. Injectors
Yesterday, while accelerating from the highway paytoll at maximum speed, i noticed a huge decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. This morning i pull out the spark plugs, three were soaked with gazoline and the fourth was dry. I put a piece of tissue over each injector hole and when I turn the engine on without sparks, the ones with gazoline jump right out. The fourth one remains closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found zero ohm. I'm assuming that the issue is elsewhere.
I also tried to reset the PID without success. The car can start when the G28 is unplugged and it runs perfectly when it is connected but it still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.
I don't know what to do. I think I've ruled everything else out. I'm afraid i may have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style sensor is identical to the G4 and they both work in get more info the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or from a parts store. It is easy to test them - just put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite ohms.
4. ECU
The ECU in our 20vt turbo (3B website AAN ABY) engines must be aware of the speed and position of the crankshaft to make decisions regarding fuel injector timing, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes badly, you will see codes on the audi spare keys diagnostic scanner that can cause the engine to shut down.
A damaged G28 sensor could result in an inaccurate speed replacement key for audi a3 counter for your gearbox or a gearbox that shifts more quickly than normal, or an unfire when in the gear. If you have any of these problems, it is most likely that your sensor is going bad and requires replacement. The good news is they are quite affordable and readily available particularly if you're looking at an Bosch sensor, like ours. You can also choose the GM version of this unit is also a good choice.
5. Tachometer
A malfunctioning engine sensor can cause a variety of issues in your car. It is an important part of the transmission of your Audi since it sends information to the ECU about how fast or slowly the car's engine is spinning. This sensor can cause what is the audi advanced key the transmission to malfunction and other components in the car to be affected.
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 an uncolored wire. The ECU then processes the signal to control fuel, timig, and boost as well as transmitting it to the G5 tachometer in the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect a resistance of approximately 1000 ohms between these two points. This is the same across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS AN and 1995 RS2 DU, so you might find good ones in wrecking yards.