Why Nobody Cares About Audi G28
Why Nobody Cares About Audi G28
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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. This sensor is situated at the edge of transmission just above the flywheel gear. It sends a message to the ECU through an uncolored wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via a grey wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft reached TDC and also the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is out of line with the Intake Camshaft. It could also be a sign of a chain stretch or a jumpy chain link in the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).
Testing is a bit challenging because there are two pins for the connector and they serve different purposes but the best method of testing it is to measure the resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is at full operation. Examine for signs of coolant or oil in the connector bay if there are issues with this part.
2. Injectors
Yesterday accelerating full speed from highway paytoll, i experienced an abrupt drop in power like the engine is running out of gas or injectors are not firing any more. Today, i pulled out the spark plugs. Three were drenched with gazoline the 4th one was dry. When I start the engine with no sparks i put tissue on the top of each hole in the injector and the 3 drenched with gazoline pop out, but the 4th one stays closed. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. Therefore, i think the issue is in another place.
I also tried to reset the PID with no success. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature of that is -49c even after unplugging it. I also new audi car key noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.
I'm not sure what to do, i believe that i've completely ruled out all other possibilities. However, i'm afraid that i might have missed something. If anyone has any suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style transmitter is identical to the G4 and both function in the 80, 100 200, UrS and RS2 cars so you can easily find 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 upwards). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to know both the position and speed of the crankshaft to make decisions regarding timing of the fuel injector, etc. In order to do this it uses a click here Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go wrong, you will receive codes on the diagnostic scanner that can cause the engine to shut down.
A failing G28 sensor can cause an inaccurate gearbox speed counter or a gearbox that shifts faster than normal, and/or an unfire when in the gear. If you are experiencing any of these issues, it is most likely that your sensor is going bad and needs replacing. The good news is they are very cheap and easy here to find, especially if you're looking at a Bosch model, like ours. Alternately, the GM version of this component is also a great option.
5. Tachometer
A faulty engine speed sensor could be a cause for numerous problems in your vehicle. It's a vital component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is rotating. This sensor can cause the transmission audi a4 car key replacement to fail and other components of the car to be affected.
The G5 engine speed sensor is located on the outside of the transmission, above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 via an uncolored wire. The ECU utilizes this signal to control fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer inside the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see the resistance to be around read more 1000 ohms between these points. This is a standard component across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good parts could be found in wrecking yards.