How to Replace an audi q3 key G28 Engine Speed Sensor

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

1. Engine Speed Sensor

The sensor is located at the edge of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 using an uncolored wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends a signal to the G5 Tachometer located in the instrument cluster.

The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can activate spark and injectors in the right way.

If this sensor fails the ECU will show the P00160 error, 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 will not appear without the additional information provided by other sensors (G4 or G40).

Testing is a bit tricky as there are two different connector pins, and they have different functions but the most effective method of testing it is to measure resistance between the sensor and the ECU. It should read about 1000 ohms when the sensor is in full operation. Look for evidence of coolant or oil in the connector bay if there are problems with this part.

2. Injectors

Yesterday, while accelerating from the highway paytoll at a high speed, i noticed a huge drop in power. It was like the engine had run out of gas. Or, my injectors weren't firing. I took out the spark plugs this morning, 3 were soaked in gasoline, and the fourth was dry. When I crank the engine without sparks, i place a tissue on top of each injector hole, the 3 drenched with gazoline jump out but the 4th one stays closed. I tested the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I assume that the problem is somewhere else.

I also tried to reset the PID but with no luck. The car is able to start if the G28 is disconnected and runs fine when it is connected but it still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62) even when it is unplugged, shows a temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar while the actual pressure is 0.0 if i crank up the engine.

I'm not sure what to do. I feel like i've pretty much eliminated everything else. But i am afraid I may have missed something. Let me know should you have any suggestions! 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 is identical to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra in a wrecking shop or parts store. It is simple to test them - just put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines must know both the position and speed of the crankshaft to determine timing of fuel injectors, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go wrong, you will receive codes on the diagnostic scanner which could cause engine shut down.

A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter, a gearbox that shifts more quickly than normal, or a misfire in the gear. It is possible that the sensor is failing and requires to be replaced if you encounter any of these symptoms. They're inexpensive and easy to locate particularly in the case of an Bosch model like ours. Alternately, GM's version this part would be an excellent choice.

5. Tachometer

A failing engine speed sensor could be the reason behind numerous issues in your vehicle. It's a vital component of your audi replacement audi a4 key key cost - Suggested Web site -'s transmission, since it relays information to the ECU about how fast or slow the car's crankshaft is rotating. If the sensor fails, it will disrupt the performance of the transmission as well as the rest of the car's components.

The G5 engine speed sensor is situated on the outside of the transmission just above the flywheel ring gear. It sends a signal to the ECU at pin T55/49 via a grey wire. The ECU utilizes this signal to regulate the amount of fuel and boost, as well as timig. It also sends it to the G5 Tachometer located in the 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 [79trace [79]) and between pin T6a/1 as well as pin T26a/12. You should observe approximately 1000 ohms resistance between those two pins. This is a typical part across the audi car keys replacement 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.