5 Laws Anyone Working In Audi G28 Should Be Aware Of

How to Replace an Audi G28 Engine Speed Sensor

In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is located near the transmission's edge over the flywheel gear. It sends a signal to the ECU via an uncolored wire (T55/49), then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via a grey wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends a signal to the G5 Tachometer located in the instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft has reached TDC and also where the camshaft lies so that it can activate the spark and injectors.

If this sensor fails, the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating the chain stretching or a jump link on the upper timing chain. However the code will not appear on its own without additional information from other sensors (G4 and G40).

Testing is a bit challenging since there are two connector pins, and they perform different functions however the best method to test it is by measuring resistance between the sensor and the ECU. If the sensor is functional, it should read approximately 1000 ohms. If you're having issues with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll i had massive power loss as if the engine was running out of gas or injectors aren't firing anymore. Today, i pulled out the spark plugs, 3 were soaked with gazoline and the 4th one was dry. I placed a tissue over each injector hole, and when i start the engine without sparks, the three with gazoline jump out. The 4th one stays closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I get 0ohm. I think the issue is somewhere else.

I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it works fine when the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The coolant temperature sensor (G62) more info shows the wrong temperature of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is 0.

I'm not certain what to do, as i feel i have pretty much completely ruled out all other possibilities. But i'm worried that i might have missed something. If anyone has any ideas please share them! 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 so you can easily find one at a wrecking yard or from a parts store. Testing them is easy by putting 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 are equipped with an ECU that has to be aware of the speed and position of the crankshaft in order to make decisions about timing of the fuel injector, for example. In order to do this it makes read more use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes badly, you will see codes on the diagnostic scanner that can cause the engine to shut down.

The signs of a failing G28 sensor include an inaccurate rev counter for the gearbox, 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 deteriorating and needs replacing. They're cheap and easy to find, especially when they're an Bosch unit like ours. Alternatively, GM's version of this component is an excellent choice.

5. Tachometer

A failing engine speed sensor could be the reason behind many issues with your vehicle. here It's an essential how much is a replacement audi key component of your Audi's transmission, as it sends information to the ECU about how the car's crankshaft is turning. When this sensor fails, it can affect the performance of the transmission as well as the other car's components.

The G5 engine speed sensor is located at the outside of the transmission above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU utilizes this signal to control fuel and boost, as well as timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on more info pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. There should be a resistance of approximately 1000 ohms in these areas. This is a common component across the Audi 80 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.