How to Replace an audi key replacement G28 Engine Speed Sensor

In this video Charles the Humble Mechanic 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 the ECU via an uncolored wire (T55/49) which is then sent to the tachometer within the instrument cluster.

1. Engine Speed Sensor

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

The sensor is used to correlate the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors accordingly.

If this sensor fails, the ECU will display an error code P00160. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also be a sign of an issue with the chain or a jump in the chain link of the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).

Testing is a bit tricky as there are two different pins for the connector and they serve different purposes however the best method of testing it is by measuring resistance between the sensor and the ECU. It should read around 1000 ohms if the sensor is at full operation. If you're having issues with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced a big cut in power like the engine is out of gas or injectors aren't firing any more. In the morning, i removed the spark plugs. Three were drenched with gazoline the 4th one was dry. I put a piece of tissue over each hole in the injector and when i start the engine with no sparks, the three with gazoline jump out. The fourth one remains shut. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. I'm assuming the issue is elsewhere.

I also tried to reset the PID but with no luck. The car key replacement audi will start when the G28 is disconnected, Audi Tt Key Programming (Https://Prince-Dean.Technetbloggers.De/) but it is running fine with the G28 connected. However, the intermittent misfire problem persists at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows an ice temperature of -49c. Also, i noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when I crank up the engine.

I'm not sure what to do. I feel like i've pretty much all other possibilities out. However, i'm afraid that i might have missed something. If anyone has any ideas please share them! TIA!

3. Fuel Pump

The fuel pump of the g28 receives signals from 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 so you can easily find one at a wrecking yard or in a local 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 end facing upwards). They should 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 to determine timing of the fuel injector, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go badly, you will see codes on the diagnostic scanner which can cause the engine to shut down.

A malfunctioning G28 sensor could cause an inaccurate speed counter for the gearbox or a gearbox that shifts faster than normal, and/or a misfire while in gear. If you experience any of these issues it is likely your sensor is failing and needs replacing. The good thing is that they are quite affordable and easy to find, especially if you're looking at the Bosch unit which is what we have. Alternatively, GM's version of this component is an excellent choice.

5. Tachometer

A malfunctioning engine sensor can cause a variety of issues in your car. It's an essential component of the transmission of your audi replacement key fob since it sends information to the ECU on how fast or slow the engine is spinning. This sensor could cause the transmission to malfunction and other car components to be affected.

The G5 engine sensor is located near the edge of the transmission, over the flywheel ring. It sends signals via gray wire to ECU pin T55/49. The ECU utilizes this signal to control the flow of fuel and boost and also timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can test for sensor failure by examining the 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 [79trace [79]), and between pin T6a/1 and pin T26a/12. It should show approximately 1000 ohms of resistance between those points. This is a common feature across the audi lost key 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 DU So, you may find some good ones in wrecking yards.