How to Replace an audi spare key G28 Engine Speed Sensor

In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is situated on the outside of the transmission, above the flywheel gear. It sends a message to the ECU through the grey wire T55/49 and then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through the grey wire. The ECU utilizes this information to control the amount of fuel and boost. It also sends an indicator to the G5 Tachometer in instrument cluster.

The sensor audi Tt Key Programming serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft reached TDC and also where the camshaft lies so that it can activate the spark and injectors.

If this sensor fails to function, the ECU will display a P00160 error code. This indicates that the Crank Shaft is not in line with the Intake Camshaft. It could also indicate an issue with the chain or a jumped chain link in the upper chain of timing. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).

Testing is a bit challenging since there are two pins for the connector and they have different functions however the best way to test it is by measuring resistance between the sensor and the ECU. It should read around 1000 ohms when it is in full operation. If you're having issues with this sensor, look for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll, i experienced massive power loss as if the engine was running out of gas or the injectors are not firing any more. I took out the spark plugs this morning and audi Tt key Programming found that 3 were drenched in gasoline and the 4th was dry. I put a piece of tissue over each injector hole, and when I start the engine without sparks, the ones with gazoline jump right out. The 4th one remains shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got zero ohm. I'm assuming that the issue is in another location.

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

I'm not sure what to do. I believe that I've all other possibilities out. However, i'm afraid that I might have missed something. If anyone has suggestions, please let me know! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style sensor is identical to the G4 and they both work in the 80 100 200, UrS and RS2 cars so you can easily find one at a wrecking yard or from a parts store. It is easy to test them - simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They should be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines requires to know the position and speed of the crankshaft to determine timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you encounter a problem with either of these, the diagnostic scanner will show codes that could cause the engine shutting down.

A malfunctioning G28 sensor could result in an inaccurate speed counter for the gearbox and a gearbox which shifts more quickly than normal, or an unfire when in gear. It is likely that your sensor is failing and requires to be replaced if you encounter any of these symptoms. They are cheap and easy-to-find particularly in the case of an Bosch model like ours. Alternately, the GM version of this unit is also a great option.

5. Tachometer

A damaged engine sensor could cause a number of problems in your vehicle. It is an important part of the transmission in your Audi tt Key programming because it relays information to the ECU regarding how fast or slow the engine of the car is spinning. When this sensor fails, it can cause problems for the transmission as well as the other car's components.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends a signal via a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate fuel and boost, as well as timig. It also relays it to the G5 Tachometer in instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. You can also check continuity between pin 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 an average resistance of 1000 ohms between these points. This is a common component across the audi car key replacement cost 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.