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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 at the edge of transmission just above the flywheel gear. It transmits a signal 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, above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer in instrument cluster.

please click the next internet page is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC and also the position of the camshaft, in order to activate the spark and injectors.

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

Testing is a bit tricky because there are two connector pins, and they perform different functions however the best method to test it is to measure resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is operating at its maximum. Look for evidence of coolant or oil in the connector bay if you are experiencing issues with this part.

2. Injectors

Yesterday, when accelerating from highway paytoll at full speed I noticed a significant reduction in power. It was as if the engine was running out of gas. Or, my injectors were not firing. I pulled out the spark plugs this morning, 3 were soaked with gasoline and the 4th was dry. When I crank the engine with no sparks i put tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th one stays shut. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero Ohm. I assume that the problem is elsewhere.

I also tried to reset the PID with no success. The car will start if the G28 is disconnected and is running fine when it is plugged in, but still has intermittent misfire issues at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is 0.

I'm not sure what to do. I believe that I've eliminated everything else. But i am afraid I may have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or a parts store. It is easy to test them: simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that has to know the position and speed of the crankshaft in order to make decisions about fuel injector timing etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes wrong, you will receive codes on the diagnostic scanner that can lead to engine shutdown.

A failing G28 sensor could cause an inaccurate speed counter for the gearbox and a gearbox which shifts faster than normal, or a misfire while in gear. It is probable that your sensor is failing and requires to be replaced if you encounter any of these symptoms. They're cheap and easy to find especially when they're a Bosch sensor like ours. If you prefer, GM's version of this component is an option.

5. Tachometer

A failing engine sensor could cause a myriad of issues in your vehicle. It's a vital component of your Audi's transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is spinning. When this sensor fails, it will affect the performance of the transmission, as well as the other car's components.

The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It transmits a signal via gray wire to ECU pin T55/49. The ECU then uses and processes this signal to control fuel, timig and boost as well as transmitting it to the G5 tachometer inside the instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. You can also check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 and pin T26a/12. There should be the resistance to be around 1000 ohms in these areas. This is a common feature across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS An and 1995 RS2 Du So, you may find them in wrecking yards.

Member since: Friday, September 27, 2024

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