How to Replace an audi a3 key replacement G28 Engine Speed Sensor

In this video, Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located at the top of the transmission above the flywheel ring gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the outside of the transmission, directly above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU utilizes this information to control the amount of fuel and boost. It also sends an indication to the G5 tachometer in the instrument cluster.

The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft reached TDC and also the location of the camshaft in order to activate 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 are not in sync and possibly indicating the chain stretching or a jump link on the upper timing chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).

Testing is a bit tricky because there are two pins for the connector and they perform different functions but the most effective method to test it is by measuring resistance between the sensor and the ECU. When the sensor is operational, it should be reading approximately 1000 ohms. If you're having issues with this part, check for evidence of coolant or oil in the connector bay.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll i had a big cut in power like the engine is running out of gas or injectors aren't firing any more. Today, i pulled out the spark plugs, 3 were soaked with gazoline and the 4th one 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 out. The 4th one remains shut. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. I assume that the problem is elsewhere.

I also tried to reset the PID but with no luck. 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 temperature sensor for the coolant (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 bars when the actual pressure is 0.

I'm not certain what to do, but i believe that i've ruled out everything else. However, i'm afraid that I may have missed something. Let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter is similar 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 by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's side). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines must know both the speed and position of the crankshaft in order to make a decision about fuel injector timing, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these go badly, you will see codes on the diagnostic scanner that could cause engine shut down.

A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter or a gearbox that shifts faster than normal, and/or a misfire while in gear. It is likely that the sensor is failing and requires to be replaced if you notice any of these symptoms. They're inexpensive and easy to locate, especially in the case of an Bosch model like ours. Alternately, the GM version of this component is also a great 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 a1 key fob smart audi tt key fob replacement audi keys, helpful site, because it relays information to the ECU on how fast or slowly the engine of the car is spinning. If this sensor fails, it can cause problems for the transmission, as well as the other car's components.

The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate fuel and boost, and also timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. You can also 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 and pin T26a/12. You should see the resistance to be around 1000 ohms between these points. This is a typical component across the audi keyless go 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.