Why You Should Focus On The Improvement Of Audi G28

How to Replace an audi car key G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates 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 sends a message to the ECU via the grey wire T55/49 and then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

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

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

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, possibly indicating the chain is stretched or a jump link on the upper timing chain. The code will audi tt key fob not working appear without the additional information supplied by other sensors (G4 or G40).

It's a bit tricky to test as there are several connector pins, and they all have different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms if the sensor is at full operation. If you are having problems with this part, check for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll, i experienced a big cut in power like the engine is out of gas or the injectors are not firing anymore. In the morning, i removed the spark plugs, three were drenched in gazoline, the fourth was dry. I put tissue over each hole in the injector and when I turn the engine on without sparks, the ones with gazoline jump right out. The 4th one remains closed. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 I got 0ohm. I assume that the problem is somewhere else.

I also tried to reset the PID without success. The car will start when the G28 is not plugged in and runs fine when it is plugged in however it has intermittent misfire issues at higher RPM. The coolant temperature sensor (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 bar but the actual pressure is 0.

I'm not sure what to do, as i think i've pretty much eliminated everything else. I'm concerned that i may have missed something. If anyone has any suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style transmitter is identical to the G4 sender, Repairer and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or a 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 end up) and 2 (2nd from left on the black end of the connector). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that must be aware of the speed and position of the crankshaft to make decisions about fuel injector timing etc. To accomplish this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these sensors, the diagnostic scanner will show codes that could cause an engine shutdown.

Some of the signs of a malfunctioning G28 sensor are an inaccurate gearbox rev counter, gears shifting quicker than normal, and/or a misfire when you're in gear. If you are experiencing any of these issues, it is likely that your sensor is going bad and needs replacing. They are cheap and easy-to-find especially when they're a Bosch unit like ours. If you prefer, GM's version of this part would be an excellent choice.

5. Tachometer

A malfunctioning engine sensor can cause a number of problems in your car. It's a vital component of your audi tt key case's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft 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 outskirts of transmission, above the flywheel ring. It sends signals via a gray wire to the ECU pin T55/49. The ECU then processes the signal to control fuel, timig, and boost and then transmitting it to the G5 tachometer inside the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see an average resistance of 1000 ohms between these two points. This is the same across the audi a3 key 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du So, you may find some good ones in wrecking yards.