How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is situated on the edge of the transmission just above the flywheel ring gear. It transmits a signal the ECU via the grey wire (T55/49) and then to the tachometer within 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 uses this information to control the flow of fuel, timig and boost. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu needs to know 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 show a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating the chain is stretched or a jump link on the upper timing chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).
It can be a bit difficult to test since there are different pins on the connector, and each one has different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is operating at its maximum. Check for signs of coolant or oil in the connector bay if you are experiencing issues with this component.
2. Injectors
Yesterday accelerating full speed from highway paytoll i had an abrupt drop in power as if the engine was running out of gas or injectors aren't firing any more. This morning i pull out the spark plugs, 3 were drenched with gazoline the fourth one was dry. When i crank the engine with no sparks i put tissue on top of each injector hole, the 3 drenched with gazoline jump 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 somewhere else.
I also tried to reset the PID but without success. The car can start if the G28 is website disconnected and it runs perfectly when it is plugged in but it still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when it is unplugged, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is zero.
I'm not sure what to do, i think i've pretty much completely ruled out all other possibilities. I'm concerned more info 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 receives signals 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 so you can easily find one at a junkyard 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 on the connector's edge facing upwards). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines requires to know both the speed and position of the crankshaft to determine fuel injector timing, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these, the diagnostic scanner will display codes that could cause the engine shutting down.
A damaged G28 sensor could result in an inaccurate speed counter for the gearbox or a gearbox that shifts faster than normal, or a misfire while in gear. If you are experiencing any of these problems, it is likely your sensor is going bad and requires replacement. The good news is they are very affordable and readily available, especially in the case of an Bosch model, which is what we have. You can also choose the GM version of this part is also a great option.
5. Tachometer
A failing engine speed sensor could be the reason behind many problems in your car. It is a crucial part of your Audi's transmission, since it relays information to the ECU about how fast or slow 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 sensor is located at the outskirts of transmission, above the flywheel ring. It sends a signal via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to regulate the audi car key flow of fuel and boost and also to timigrate. It also relays it to the G5 Tachometer in 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 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 1000 ohms between these two points. This is a typical part across the Audi 80, 100 read more 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good parts click here could be found in wrecking yards.