How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located on the outside of the transmission, above the flywheel gear. It transmits a signal to the ECU via an uncolored wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through the grey wire. The ECU utilizes this information to control boost and fuel. It also sends an indication to the G5 Tachometer within the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu must know when the crankshaft reached TDC, and the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is out of sync with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumpy chain link in the upper chain. 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 connector pins, and they have different functions however the best method of testing it is to measure the resistance between the sensor and the ECU. audi spare key replacement should read around 1000 ohms if the sensor is at full operation. Examine for evidence 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 an abrupt drop in power like the engine is running out of gas or injectors aren't firing any more. This morning i pull out the spark plugs. Three were drenched with gazoline the fourth was dry. When I start the engine without sparks i put tissue on top of each injector hole and the 3 that were drenched in gazoline leap out, however the 4th stay closed. I checked the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got 0ohm. So i assume the problem is somewhere else.
I also tried to reset the PID but without success. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However, the intermittent misfire problem continues to occur at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value -49c, even if I unplug it. Also i noticed that the gauge for oil pressure in the cockpit is showing 2 bar when the actual pressure is 0.0 when i rev the engine.
webpage don't know what to do. I think I've eliminated everything else. However, i'm afraid that I might have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate the spare in a salvage shop or parts store. Testing them is easy - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black end of the connector). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines needs to know both the speed and position of the crankshaft to make decisions regarding fuel injector timing, etc. audi a4 car key replacement uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you are experiencing issues with either one of these, the diagnostic scanner will display codes that could lead to an engine shutdown.
A malfunctioning G28 sensor could result in an inaccurate speed counter for the gearbox, a gearbox that shifts more quickly than normal, and/or a misfire in gear. It is likely that the sensor is failing and needs to be replaced if you experience any of these signs. The good news is that they are very cheap and readily available, especially if you're looking at an Bosch model, like ours. If you prefer, GM's version of this part is an option.
5. Tachometer
A damaged engine sensor could cause a number of problems in your vehicle. It is an important part of the transmission in your Audi, as it transmits information to the ECU on how fast or slow the engine is turning. If this sensor fails, it will disrupt the performance of the transmission, as well as the rest of the car's components.
The G5 engine speed sensor is located at the edge of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU utilizes this signal to regulate fuel and boost, and also timig. It also relays it to the G5 Tachometer in instrument cluster. You can determine if the sensor is in failure by examining the 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 [79trace [79]), and between pin T6a/1 as well as pin T26a/12. You should observe approximately 1000 ohms resistance between those two pins. This is a common feature across the Audi 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 DU So, you may find good ones in wrecking yards.