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. This sensor is situated on the outside of the transmission just above the flywheel gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, directly above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends signals to the G5 tachometer inside the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors accordingly.
If this sensor fails when it fails, the ECU will display an error code P00160. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also be a sign of an issue with the chain or a jump in the chain link of the upper chain of timing. The code won't show without the additional information provided by other sensors (G4 or G40).
Testing is a bit challenging as there are two different pins for the connector and they serve different purposes but the best method of testing it is by measuring resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is in full operation. If you're having issues with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced massive power loss like the engine is running out of gas or injectors aren't firing at all. This morning i pull out the spark plugs. Three were drenched with gazoline the fourth one was dry. When I start the engine with no sparks, i place a tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th one stays closed. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 I got zero Ohm. So i assume the problem is elsewhere.
I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value that is -49c even after unplugging it. Also i noticed that the oil pressure gauge in the cockpit is showing 2 bar when the actual pressure is 0.0 when I crank up the engine.
I don't know what to do. I believe that I've eliminated everything else. I'm concerned that i may have missed something. If anyone has any ideas please let me know! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or a parts store. It is easy to test them: simply 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 should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines requires to be aware of the position and speed the crankshaft in order to make a decision check here about fuel injector timing, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these sensors, the diagnostic scanner will show the codes that could trigger an engine shutdown.
A failing G28 sensor could read more result in an inaccurate gearbox speed counter, a gearbox that shifts faster than normal, and/or a misfire in gear. It is probable that the sensor is failing and needs to be replaced if you experience any of get more info these symptoms. They are cheap and easy-to-find especially in the case of a Bosch model like ours. Alternately, the GM version of this unit is also a good choice.
5. Tachometer
A faulty engine speed sensor could be a cause for many issues with your car. It's a crucial component of the transmission of your Audi because it relays information to the ECU on how fast or slow the engine is spinning. This sensor can cause the transmission to fail and other components in the car to be affected.
The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends signals here via an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to regulate the amount of fuel and boost, as well as timig. It also relays it to the G5 Tachometer click here inside the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see approximately 1000 ohms resistance between these two points. This is a common part across the Audi 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.