How to Replace an audi spare keys G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is situated near the edges of the transmission just above the flywheel ring gear. It transmits a signal to the ECU via the grey wire (T55/49), then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends signals to ECU pin T55/49 via a grey wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an indicator to the G5 Tachometer in instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors accordingly.
If this sensor fails to function, the ECU will display an error code P00160. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumped chain link in the upper chain of timing. The code will not appear without the additional information provided by other sensors (G4 or G40).
Testing can be a bit difficult because there are two connector pins 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 about 1000 ohms when the sensor is at full operation. Look for evidence of coolant or oil in the connector bay if you are experiencing problems with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll i had a big cut in power like the engine is running out of gas or injectors are not firing anymore. Today, i pulled out the spark plugs, 3 were drenched with gazoline the 4th one was dry. When I start the engine with no sparks, i place a tissue on the top of each hole in the injector audi A1 key and the 3 that were drenched in gazoline jump out but the 4th one stays shut. I tested the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. I’m assuming the issue is somewhere else.
I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and it works fine when the G28 plugged in. However, the intermittent misfire problem still occurs 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 but the actual pressure is zero.
I’m not certain what to do, as i think i’ve pretty much completely ruled out all other possibilities. I’m concerned that i may have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal sent by the RPM sensor. The GM-style sensor 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 at a parts store. It is easy to test them – just put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines must know the position and speed the crankshaft to make decisions regarding timing of the fuel injector, etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go badly, you will see codes on the diagnostic scanner that could cause engine shut down.
A malfunctioning G28 sensor could result in an inaccurate speed counter for the gearbox and a gearbox which shifts faster than normal, or a misfire in gear. If you are experiencing any of these problems, it is likely that your sensor is going bad and requires replacement. They are cheap and easy-to-find particularly when they’re a Bosch sensor like ours. You can also choose the GM version of this component is also a great option.
5. Tachometer
A failing engine speed sensor could be the cause of many issues with your vehicle. It’s an essential component of your audi q7 replacement key‘s transmission, since it relays information to the ECU about how the car’s crankshaft is turning. When this sensor fails, it can cause problems for the transmission, as well as the rest of the car’s components.
The G5 engine sensor is located near the edge 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 then processes the signal to control fuel, timig and boost and then sends it on to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by examining 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. It should show approximately 1000 ohms resistance between these two points. This is a standard part across the key audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.
