How to Replace an audi key programmer G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is located at the top of the transmission above the flywheel ring gear. It transmits a signal the ECU via a grey wire (T55/49) which is then sent to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is located on the outside of the transmission, just above the flywheel ring. This 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 an indication to the G5 Tachometer within the instrument cluster.

The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft has reached TDC, and where the camshaft lies to trigger the spark and injectors.

If this sensor fails the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren't in sync and could indicate chain stretch or a jumped link on the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).

It is a little tricky to test as there are several pins on the connector and each has its own functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms when it is operating at its maximum. Look for evidence of coolant or oil in the connector bay if you have issues with this component.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced a big cut in power like the engine is running out of gas or injectors are not firing anymore. I pulled out the spark plugs this morning, three were soaked in gasoline, and the 4th was dry. I put tissue over each hole in the injector and when i start the engine with no sparks, the 3 with gazoline jump out. The 4th one stays shut. I checked the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I get zero Ohm. I'm assuming the issue is elsewhere.

I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is 0.

I don't know what to do. I think I've all other possibilities out. However, i'm afraid that i might have missed something. If anyone has any ideas please chime in! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal sent by the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or a parts store. Test them out by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black connector's end). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines must know both the position and audi a3 key fob replacement key for audi - Images.google.com.gt, speed of the crankshaft to determine timing of fuel injectors, etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these sensors, the diagnostic scanner will display the codes that could trigger an engine shut down.

Some of the signs of a malfunctioning G28 sensor are an inaccurate rev counter in the gearbox the gears are shifting faster than normal and/or misfiring when you're in gear. It is possible that the sensor is failing and needs to be replaced if you encounter any of these signs. The good news is that they are quite affordable and easily accessible, especially if you're looking at an Bosch sensor, which is what we have. Alternatively, the GM version of this unit is also a great option.

5. Tachometer

A malfunctioning engine sensor can cause a variety of issues in your vehicle. It's an essential component of the transmission of your audi keys replacement cost because it relays information to the ECU on how fast or slow the engine of the car is spinning. When this sensor fails, it could disrupt the performance of the transmission as well as the other car's components.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU is then able to process the signal to control the flow of fuel, timig and boost, and also sends it on to the G5 Tachometer located in the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. You can also verify continuity between pin 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 observe approximately 1000 ohms resistance between those two pins. This part is common across the audi a5 key fob 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 DU So, you may find some good ones in wrecking yards.