How to Replace an audi keyless go G28 Engine Speed Sensor

In this video, Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located at the edge of transmission over the flywheel gear. It sends a message to the ECU through an uncolored wire T55/49, then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the outside of the transmission, just above the flywheel ring. The 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 inside the instrument cluster.

The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft reached TDC and also where the camshaft lies in order to activate the spark and injectors.

If this sensor fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of sync 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 timing chain. The code won't appear without the additional information provided by other sensors (G4 or G40).

It's a bit tricky to test since there are various pins on the connector and each one has different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. When the sensor is operational, it should read approximately 1000 ohms. Examine for signs of coolant or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at a high speed I noticed a significant drop in power. It was as if the engine was running out of gas. Or, my injectors weren't firing. Today, i pulled out the spark plugs, 3 were soaked with gazoline and the fourth one was dry. I placed a tissue over each hole in the injector and when i turn the engine on without sparks, the ones that have gazoline pop right out. The 4th one remains closed. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero ohm. I'm assuming the issue is in another place.

I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it works fine when the G28 connected. However the intermittent misfire issue persists at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of that is -49c even after unplugging it. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar when the actual pressure is 0.0 when I crank up the engine.

I'm not certain what to do, as i believe that i've completely ruled out all other possibilities. I'm worried that i might have missed something. If anyone has suggestions, please let me know! 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 they both work in the 80, 100 200, UrS and RS2 cars so you can easily find one at a junkyard or at a parts store. Test them out - 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

Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that must know the position and speed of the crankshaft in order to make a decision about fuel injector timing etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes bad you will get codes on the diagnostic scanner which can lead to engine shutdown.

A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter, a gearbox that shifts faster than normal, or an unfire when in the gear. If you have any of these issues it is likely that your sensor is failing and requires audi a4 replacement key. The good thing is that they are very cheap and easily accessible, especially if you're looking at the Bosch model, like ours. Alternately, the GM version of this component is also a good choice.

5. Tachometer

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

The G5 engine speed sensor is situated on the edge of the transmission just above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 via an uncolored wire. The ECU is then able to process this signal to regulate the flow of fuel, timig and boost as well as transmitting it to the G5 tachometer in the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to 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 points. This is a common feature across the audi spare keys audi key fob not working replacement cost (bestspeed.lv) 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU You may also find them in wrecking yards.