How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is situated at the edge of transmission, 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
The grey wire is located on the outside of the transmission, just above the flywheel ring. This sensor sends an electrical signal 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 know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors according to the situation.
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 chain stretch or a jumped link on the upper timing chain. The code won't show 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 perform different functions but the most effective method of testing it is to measure resistance between the sensor and the ECU. When the sensor is fully operational, it should be reading about 1000 ohms. Look for signs of coolant or oil in the connector bay if there are problems with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced a big cut in power as if the engine was running out of gas or injectors are not firing any more. This morning i pull out the spark plugs, three were drenched with gazoline the 4th one was dry. When I start the engine with no sparks, i place a tissue on top of each injector hole and the 3 that were drenched in gazoline pop out, but the 4th one stays closed. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. i get zero Ohm. I think the issue is in another location.
I also tried to reset the PID without success. simply click the up coming article will start when the G28 is unplugged, and it works fine when the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.
I'm not sure what to do, as i think i've pretty much ruled out everything else. I'm afraid i may have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal from the RPM sensor. lost my audi car keys -style sender 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 - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector's end facing up). lost audi key should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to know both the position and speed the crankshaft in order to make a decision about fuel injector timing, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either one of these, the diagnostic scanner will show codes that could cause the engine shutting down.
A malfunctioning G28 sensor could cause an inaccurate speed counter for your gearbox, a gearbox that shifts faster than normal, and/or an unfire when in the gear. If you experience any of these issues it is most likely that your sensor is going bad and should be replaced. They are cheap and easy-to-find, especially in the case of a Bosch sensor like ours. You can also choose the GM version of this component is also a good option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for a slew of issues in your vehicle. It's a vital component of your Audi's transmission, as it sends information to the ECU about how the car's crankshaft is turning. This sensor could cause the transmission to malfunction and other components in the car to be affected.
The G5 engine speed sensor is located at the edge of the transmission just above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU then processes this signal to control the flow of fuel, timig and boost and then transmitting it to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. Also, you can check continuity between pin 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 see an average resistance of 1000 ohms in these areas. This is the same across the Audi 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS AN and 1995 RS2 Du So, you may find some good ones in wrecking yards.