How to Replace an Audi G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located near the transmission's edge over the flywheel gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 using the grey wire. The ECU utilizes this information to regulate boost and fuel. It also sends an indicator to the G5 Tachometer within the instrument cluster.

The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can start spark and injectors according to the situation.

If this sensor fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of a chain stretch or a jumped chain link in the upper chain of timing. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).

Testing can be a bit difficult as there are two different connector pins, and they perform different functions but the best method of testing it is by measuring resistance between the sensor and the ECU. It should read around 1000 ohms when it is operating at its maximum. If you are having problems with this part, check for signs of oil or coolant in the connector bay.

2. Injectors

Yesterday, when accelerating from highway paytoll at full speed, i noticed a huge drop in power. It was like the engine was running out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs. Three were soaked with gazoline and the fourth was dry. I placed a tissue over each injector hole and when i start the engine without sparks, the ones that have gazoline pop right out. The 4th one remains closed. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got zero Ohm. So i assume the problem is somewhere else.

I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and 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 temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is zero.

I'm not certain what to do, as i feel i have pretty much completely ruled out all other possibilities. I'm concerned that i may have missed something. Let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work on the audi replacement key 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or parts store. It is simple to test them by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left read more on the black connector's end). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines must know both the position and speed the crankshaft to determine timing of fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you are experiencing issues with either of these, the diagnostic scanner will display codes that could lead to the engine shutting down.

A failing G28 sensor can cause an inaccurate gearbox speed counter, a gearbox that shifts more quickly than normal, and/or a misfire while in the gear. If you are experiencing audi car key any of these issues, it is likely your sensor is deteriorating and should be replaced. They're inexpensive and easy to locate especially when they're an Bosch unit like ours. You can also choose the GM version of this unit is also a great option.

5. Tachometer

A malfunctioning engine speed sensor could be the reason behind numerous issues in your vehicle. It is an important part of the transmission of your Audi, as it transmits information to the ECU about how fast or slow the car's engine is turning. This sensor could cause the transmission to malfunction and other components in the car to be affected.

The more info G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU then processes this signal to regulate fuel, timig, and boost as well as transmitting it to the G5 Tachometer located in the instrument cluster. You can check the sensor for failure by checking continuity between it and the car key replacement audi tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect the resistance to be around 1000 ohms in these areas. This is a common feature across the Audi 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 DU You may also find good ones in wrecking yards.