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 on the edge of the transmission, above the flywheel ring gear. It transmits a signal the ECU via an uncolored wire (T55/49) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, above the flywheel ring. This sensor sends a signal via 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 as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft reached TDC and also the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain is stretched or a jump link on the upper chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).
Testing can be a bit difficult as there are two different connector pins, and they perform different functions but the most effective method to test it is to measure resistance between the sensor and the ECU. When the sensor is fully functional, it should read approximately 1000 ohms. If you are having problems with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at maximum speed, i noticed a huge decrease in power. It was as if the engine was running out of gas. Or, my injectors were not firing. Today, i pulled out the spark plugs, three were soaked with gazoline and the fourth was dry. I put a piece of tissue over each injector hole, and when I start the engine with no sparks, the ones with gazoline jump right out. The 4th one stays shut. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. I'm assuming that the issue is in another location.
I also tried to reset the PID without success. The car can start if the G28 is not plugged in and it runs perfectly when it is plugged in, but still has the intermittent misfire issue at higher RPM. The coolant sensor (G62) even when unplugged, website still shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.
I'm not sure what to do, i believe that i've eliminated everything else. However, i'm afraid that i might have missed something. Let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style transmitter is identical to the G4 and both function in the 80, 100 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or in a local parts store. It is easy to test them - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that must know the speed and position of the crankshaft in order to make decisions regarding fuel injector timing etc. It makes use of a Crank Position Sensor G4 and an Engine more info Speed Sensor G28 to accomplish this. If you have a problem with either of these sensors, the diagnostic scanner will show the codes that could trigger an engine shutdown.
Some of the symptoms of a failed G28 sensor are an inaccurate rev counter in the gearbox and gears that shift faster than normal and/or misfiring when in gear. It is likely that your sensor is failing and needs to be replaced if you experience any of these signs. They're cheap and easy to find especially when they're an Bosch sensor like ours. Alternatively, GM's version of this part is an excellent choice.
5. Tachometer
A malfunctioning engine speed sensor could be the cause of a slew of issues with your car. It is a crucial part of the Audi's transmission because it communicates to the ECU about how the car's crankshaft is spinning. This sensor can cause the transmission to fail and other components of the car to be affected.
The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. audi a1 car key It transmits a signal via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to regulate read more the flow of fuel and boost as well as timig. It also transmits it to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. It should show approximately 1000 ohms of resistance between those two pins. This part is common across the Audi audi convenience key 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 some good ones in wrecking yards.