How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is situated at the top of the transmission above the flywheel ring gear. It transmits a signal to the ECU via a grey wire (T55/49), then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the outside of the transmission, above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU uses this information to control fuel and boost. It also sends an indicator to the G5 Tachometer within the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware 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 display a P00160 error code. This means that the Crank Shaft is out of sync with the Intake Camshaft. It could also indicate a chain stretch or a jumpy chain link in the upper timing chain. However the code will not appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit challenging since there are two connector pins, and they serve different purposes however the best method to test it is to measure the resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is in full operation. If you are having problems with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at maximum speed I noticed a massive drop in power. It was as if the engine had run out of gas. Or, my injectors were not firing. In the morning, i removed the spark plugs, three were drenched with gazoline the fourth one was dry. When i crank the engine without sparks, i place a tissue on top of each injector hole and the 3 that were drenched in gazoline leap out, however the 4th one stays shut. I tested the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. Therefore, i think the issue is somewhere else.
I also tried to reset PID but without success. The car is able to start if the G28 is not plugged in and is running fine when it is connected, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when it is unplugged, shows an ice temperature of -49c. Also i noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the read more actual pressure is 0.0 when i rev the engine.
I'm not sure what to do. I believe that I've all other possibilities out. But i'm worried that I may have missed something. If anyone has any ideas please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style sensor is the same as the G4 and both function in the 80 more info 100 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or at click here a parts store. It is simple to test them - just put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that read more needs to know the position and speed of the crankshaft to make decisions regarding timing of the fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either one of these, the diagnostic scanner will display the codes that read more could trigger an engine shutdown.
The signs of a failing G28 sensor include an inaccurate rev counter for the gearbox and gears that shift faster than normal, and/or a misfire when you're in gear. If you are experiencing any of these issues it is likely that your sensor is deteriorating and needs replacing. The good news is that they are very affordable and easy to find particularly in the case of a Bosch sensor, like ours. You can also choose the GM version of this part is also a good choice.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for many issues in your vehicle. It's an essential component of the transmission of your Audi since it sends information to the ECU regarding how fast or slow the engine is spinning. This sensor can cause the transmission to malfunction and other components of the car to be affected.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It sends an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU uses this signal to regulate the flow of fuel and boost and also timig. It also transmits it to the G5 Tachometer inside the instrument cluster. You can check for sensor failure by checking continuity from the sensor to the tachometer. Additionally, you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 as well as pin T26a/12. You should detect an average resistance of 1000 ohms between these points. This part is common across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du You may also find good ones in wrecking yards.