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 on the outside of the transmission over the flywheel gear. It transmits a signal the ECU via a grey wire (T55/49), then to the tachometer in 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 an electrical signal to ECU pin T55/49 through a grey wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends signals to the G5 tachometer inside the instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors in the right way.

If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync, possibly indicating chain stretch or a jumped link on the upper chain of timing. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).

Testing is a bit challenging because there are two connector pins, and they perform different functions but the best method to test it is by measuring resistance between the sensor and the ECU. If the sensor is operational, it should be reading around 1000 ohms. If you are having problems with this component, look for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, while accelerating from the highway paytoll at maximum speed, i noticed a huge decrease in power. It was as if the engine was running out of gas. Or, my injectors were not firing. This morning i pull out the spark plugs, three were soaked with gazoline and the fourth was dry. When I crank the engine without sparks, i place a tissue on the top of each of the injector holes and the 3 drenched with gazoline leap out, however the 4th stays closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got 0ohm. So i assume the problem is somewhere else.

I also tried to reset PID but without success. The car will start when the G28 is not plugged in and it runs perfectly when it is plugged in, but still has the intermittent misfire issue at higher RPM. The coolant sensor (G62) even when unplugged, still shows a temperature of -49c. Also, i noticed that the gauge for oil pressure in the cockpit is showing 2 bar when the actual pressure is 0.0 when I crank up the engine.

I don't know what to do. I feel like i've pretty much all other possibilities out. I'm concerned that i may have missed something. If anyone has any suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style sensor is identical to the G4 and both function in the 80, 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or from a parts store. It genuine audi key replacement is easy to test them - just put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that has to know the position and speed of the crankshaft in order to make a decision about fuel injector timing etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either one of these, the diagnostic scanner will show codes that could lead to audi spare key an engine shutdown.

A damaged G28 sensor could result in an inaccurate speed counter for your gearbox and a gearbox which shifts more quickly than normal, and/or a misfire while in gear. If you have any of these issues it is likely your sensor is going bad and requires replacement. The good news is that they are very cheap and easy to find, especially if you're looking at a Bosch unit which is click here what ours are. You can also choose the GM version of this unit is also more info a great option.

5. Tachometer

A failing engine speed sensor could be a cause for many problems in your vehicle. It's an essential component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is rotating. If this sensor fails, it can cause problems for the transmission as well as the rest of the car's components.

The G5 engine speed sensor is located on the outside of the transmission above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 via an uncolored audi a4 key replacement wire. The ECU is then able to process the signal to control the flow of fuel, timig and boost as well as transmitting it to the G5 tachometer in the instrument cluster. You can determine if the sensor is in failure by checking continuity from the sensor to the tachometer. You can also examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 as well as pin T26a/12. You should see an average resistance of 1000 ohms in these areas. This is the same across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS An and 1995 RS2 Du So, you may find good ones in wrecking yards.