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 on the edge of the transmission, above the flywheel ring gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU uses this information to regulate boost and fuel. It also sends an indicator to the G5 Tachometer within the instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu must be aware of when the crankshaft has reached TDC and also where the camshaft lies in order to activate the spark and injectors.
If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumpy chain link in the upper chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit challenging because there are two connector pins, and they perform different functions but the most effective method of testing it is to measure the resistance between the sensor and the ECU. It should read around 1000 ohms when it is operating at its maximum. Look for evidence of coolant or oil in the connector bay if you have issues with this part.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at full speed, i noticed a huge drop in power. It was as if the engine had run out of gas. Or my injectors weren't firing. I took out the spark plugs this morning, three were soaked with gasoline and the fourth was dry. When i crank the engine with no sparks, I put a piece of tissue on the top of each hole in the injector and the 3 drenched with gazoline pop out, but the 4th stays closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got zero ohm. I'm assuming that the issue is in another location.
I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. I also noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when i rev the engine.
I'm not sure what to do. I think I've ruled everything else out. But i am afraid I might have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal from the RPM sensor. The GM-style sensor is identical to the G4 and both function in 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. Testing them is easy - put your DMM audi a4 spare key 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 end of the connector). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to know both the position and speed of the crankshaft to determine timing of the fuel injector, etc. It utilizes a Crank Position Sensor G4 audi key replacement and an Engine Speed Sensor G28 to accomplish this. If either of these sensors go bad you will get codes on the diagnostic scanner which can cause the engine to shut down.
A damaged G28 sensor could cause an inaccurate speed counter for the gearbox and a gearbox which shifts faster than normal, or a misfire while in gear. If you are experiencing any of these issues it is likely that your sensor is deteriorating and needs replacing. They're inexpensive and easy to locate especially in the case of an Bosch model like ours. You can also choose the GM version of this unit is also a good option.
5. Tachometer
A faulty engine speed sensor could be the reason behind numerous problems in your vehicle. It is a crucial part of the Audi's transmission because it communicates to the ECU about how fast or slow the car's crankshaft is spinning. This sensor can cause the transmission to fail and get more info other components in the car to be affected.
The G5 engine speed sensor is located on the edge of the transmission above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49 via an uncolored wire. The ECU is then able to process this signal to regulate the flow of fuel, timig and boost and then transmitting it to the G5 tachometer inside the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to audi a3 key replacement the tachometer. Also, you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 and pin T26a/12. You should detect an average resistance of 1000 ohms between these points. This is a standard component across the Audi 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones audi key programming near me might be availble in wrecking yards.