How to Replace an audi a3 keys G28 Engine Speed Sensor

Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is located near the edges of the transmission just above the flywheel ring gear. It transmits a signal to the ECU via the grey wire T55/49 and then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is located on the edge of transmission, above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU utilizes this information to regulate the amount of fuel and boost. It also sends an alert to the G5 Tachometer within the instrument cluster.

The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors in the right way.

If this sensor fails the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft are not in sync and could indicate chain stretch or a jumped link on the upper chain of timing. The code won't show without the additional information supplied by other sensors (G4 or G40).

It is a little tricky to test as there are various connector pins, and each has its own functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. When the sensor is operational, it should read approximately 1000 ohms. Look for signs 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 had massive power loss like the engine is running out of gas or the injectors aren't firing anymore. Today, i pulled out the spark plugs, three were drenched with gazoline the 4th one was dry. I placed a tissue over each injector hole, and when I turn the engine on without sparks, the 3 that have gazoline pop right out. The 4th one remains shut. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero ohm. I'm assuming the issue is in another place.

I also tried to reset the PID but with no luck. The car will start when the G28 is unplugged, and it is running fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62) even when unplugged, still shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is 0.

I'm not certain what to do, as i believe that i've 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 on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is the same as the G4 and both are used in the 80, 100 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or from a parts store. It is simple to test them: simply put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that needs to know the speed and position of the crankshaft in order to make decisions regarding timing of the fuel injector, for example. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes bad you will get codes on the diagnostic scanner which can cause the engine to shut down.

A failing G28 sensor could cause an inaccurate speed counter for the gearbox, a gearbox that shifts more quickly than normal, or a misfire while in gear. If you experience any of these problems, it is likely your sensor is going bad and requires replacement. They are cheap and easy-to-find particularly if they're a Bosch sensor like ours. Alternatively, GM's version of this part would be a good option.

5. Tachometer

A failing engine sensor could cause a number of problems in your vehicle. It is an important part of the transmission in your audi replacement key since it sends information to the ECU regarding how fast or slow the engine is spinning. When this sensor fails, it will affect the performance of the transmission and the rest of the car's components.

The G5 engine speed sensor is located on the edge of the transmission just above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49, via an uncolored wire. The ECU utilizes this signal to regulate fuel and boost, and also timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. It should show approximately 1000 ohms of resistance between those two pins. This is a common component across the audi tt replacement key replacement audi key cost key audi Service - Ezproxy.cityu.edu.hk - 80 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU so good parts could be found in wrecking yards.