lungcomma5

How to Replace an Audi G28 Engine Speed Sensor Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is situated on the edge of the transmission above the flywheel ring gear. It transmits a signal to the ECU through an uncolored wire T55/49, then to the tachometer on the instrument cluster. 1. Engine Speed Sensor The grey wire is located at the edges of the transmission, above the flywheel ring. The sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then uses this information to control fuel, timig and boost. 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 must know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors according to the situation. If this sensor fails when it fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate a chain stretch or a jumpy chain link in the upper chain of timing. The code won't show without the additional information supplied by other sensors (G4 or G40). Testing can be a bit difficult as there are two different pins for the connector and they perform different functions but the best method of testing it is to measure the resistance between the sensor and the ECU. If the sensor is operational, it should read about 1000 ohms. If you're experiencing issues with this sensor, look for signs of coolant or oil in the connector bay. 2. Injectors Yesterday accelerating full speed from highway paytoll, I experienced an abrupt drop in power as if the engine was running out of gas or injectors aren't firing anymore. This morning i pull out the spark plugs, 3 were soaked with gazoline and the fourth was dry. I put tissue over each injector hole and when I turn the engine on without sparks, the 3 with gazoline jump right out. The 4th one remains shut. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 I get zero ohm. I'm assuming that the issue is elsewhere. I also tried to reset the PID 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 persists at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is zero. I'm not certain what to do, as i feel i have pretty much completely ruled out all other possibilities. I'm worried that i might have missed something. Let me know should you have any suggestions! TIA! 3. Fuel Pump The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. www.g28carkeys.co.uk can easily find an extra in a wrecking shop or parts store. It is simple to test them to do – just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's side). They must be infinite ohms. 4. ECU The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to be aware of the speed and position of the crankshaft to determine timing of fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these go wrong, you will receive codes on the diagnostic scanner which can cause the engine to shut down. A damaged G28 sensor could cause an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, and/or an unfire when in gear. It is probable that your sensor is failing and needs to be replaced if you notice any of these symptoms. They are cheap and easy-to-find particularly in the case of an Bosch unit like ours. Alternately, GM's version this part is a good option. 5. Tachometer A failing engine sensor could cause a myriad of issues in your vehicle. It's a vital component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is turning. This sensor could cause the transmission to fail and other components in the car to be affected. The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to regulate the amount of fuel and boost, and also timig. It also sends 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 verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. You should detect an average resistance of 1000 ohms between these points. 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 You may also find some good ones in wrecking yards.