The Three Greatest Moments In Audi G28 History

How to Replace an Audi A1 keys G28 Engine Speed Sensor

Charles the Humble Technician teaches you 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 an uncolored wire T55/49, then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is located on the outside of the transmission, above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU uses this information to control fuel and boost. It also sends an indication to the G5 Tachometer in instrument cluster.

The sensor is used to connect the G40 Camshaft position Sensor. The ecu must be aware of when the crankshaft has reached TDC, and the position of the camshaft, to trigger the spark and injectors.

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 and could indicate the chain is stretched or a jump link on the upper chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).

It's a bit tricky to test since there are different connector pins, and they all have different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. If the sensor is operational, it should read about 1000 ohms. If you are having problems with this part, check for evidence of coolant or oil in the connector bay.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, I experienced an abrupt drop in power 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, 3 were soaked in gasoline, and the fourth was dry. When I crank the engine without sparks i put tissue on the top of each of the injector holes, the 3 drenched with gazoline jump out but the 4th one stays shut. 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 PID without success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However the intermittent misfire issue still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.

I don't know what to do. I think I've all other possibilities out. However, i'm afraid that I may have missed something. If anyone has any ideas please share them! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal from the RPM sensor. The GM-style sender is the same as the G4 and both function 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 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 end facing up). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to know the position and speed of the crankshaft to make decisions about timing of the fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you encounter a problem with either of these sensors, the diagnostic scanner will show codes that could cause the engine shutting down.

A damaged G28 sensor can cause an inaccurate speed counter for the gearbox and a gearbox which shifts more quickly than normal, or a misfire in gear. If you have any of these problems, it is likely your sensor is going bad and should be replaced. The good thing is that they are very affordable and easy to find, especially if you're looking at an Bosch unit like ours. If you prefer, audi key shell, www.1v34.Com, GM's version of this part is a good option.

5. Tachometer

A failing engine speed sensor could be a cause for numerous problems in your vehicle. It's an essential component of the transmission in your programming audi key since it sends information to the ECU about how fast or slowly the engine is spinning. This sensor can cause the transmission to fail and other components in the car to be affected.

The G5 engine speed sensor is located at the outside of the transmission just above the flywheel ring gear and sends a signal to the ECU at pin T55/49 via an uncolored wire. The ECU utilizes this signal to regulate the amount of fuel and boost, and also timig. It also transmits it to the G5 Tachometer in instrument cluster. You can determine if the sensor is in failure by checking 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 and pin T26a/12. You should detect an average resistance of 1000 ohms between these points. This is a standard component across the audi a3 spare key 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good parts could be found in wrecking yards.