How to Replace an Audi key Replacement Cost Uk G28 Engine Speed Sensor

In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is located at the top of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer within the instrument cluster.

1. Engine Speed Sensor

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

The sensor is used to link with the G40 Camshaft position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC and also where the camshaft lies to trigger the spark and injectors.

If this sensor fails the ECU will display the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and possibly indicating chain stretch or a jumped link on the upper chain of timing. The code will audi tt key fob not working appear without the additional information supplied by other sensors (G4 or G40).

Testing is a bit tricky since there are two connector pins, and they have different functions however the best way to test it is to measure resistance between the sensor and the ECU. If the sensor is operational, it should be reading around 1000 ohms. Check for evidence of coolant or oil in the connector bay if you have issues with this part.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced massive power loss like the engine is out of gas or the injectors aren't firing anymore. In the morning, i removed the spark plugs, three were drenched in gazoline, the fourth was dry. I put a piece of tissue over each hole in the injector and when i start the engine without sparks, the ones with gazoline jump right out. The 4th one stays shut. I tested the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. So i assume the problem is somewhere else.

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

I'm not certain what to do, as i feel i have pretty much ruled out everything else. I'm worried that i might have missed something. If anyone has any ideas please let me know! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal by the RPM sensor. The GM-style sensor is identical to 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 wrecking yard or at a parts store. Testing them is easy - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black end of the connector). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY ADU) engines requires to know both the position and speed of the crankshaft in order to make a decision about timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these go bad you will get codes on the diagnostic scanner which can lead to engine shutdown.

Some of the symptoms of a failed G28 sensor are an inaccurate rev counter for the gearbox the gears are shifting faster than normal and/or a misfire when you are in gear. It is likely that the sensor is failing and requires to be replaced if you encounter any of these symptoms. The good news is that they are quite affordable and easily accessible, especially if you're looking at a Bosch unit like ours. Alternately, GM's version this part would be an excellent choice.

5. Tachometer

A faulty engine speed sensor could be the cause of numerous issues with your vehicle. It's a vital component of the replacement audi key cost's transmission as it sends information to the ECU about how the car's crankshaft is turning. This sensor could cause the transmission to malfunction and other car components to be affected.

The G5 engine speed sensor is located at the outside of the transmission above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU then uses and processes this signal to regulate the flow of fuel, timig and boost and then sends it on to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. Additionally, you can examine the continuity between pins 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 see the resistance to be around 1000 ohms between these two points. This is the same across the audi replacement key service 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du, so you might find good ones in wrecking yards.