How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is located near the transmission's edge over the flywheel gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using a grey wire. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors accordingly.
If this sensor fails the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren't in sync and could indicate the chain stretching or a jump link on the upper timing chain. However, the error code won't appear 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 have different functions but the best way to test it is by measuring resistance between the sensor and the ECU. When the sensor is fully functional, it should read approximately 1000 ohms. If you are having problems with this part, check for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed I noticed a massive reduction in power. It was as if the engine had run out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs, 3 were drenched in gazoline, the fourth one was dry. When i crank the engine without sparks, i place a tissue on top of each injector hole and the 3 drenched with gazoline jump out but the 4th one 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 elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.
I don't know what to do. I believe that I've all other possibilities out. I'm worried that i might have missed something. Please let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal from the RPM sensor. The GM-style sender 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 at a parts store. It is simple to test them: simply put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines must be aware of the position and speed of the crankshaft in order to make a decision about timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes badly, you will see codes on the diagnostic scanner which can lead to engine shutdown.
new audi key damaged G28 sensor could cause an inaccurate gearbox speed counter or a gearbox that shifts more quickly than normal, or a misfire in the gear. If you experience any of these issues, it is likely that your sensor is deteriorating and requires replacement. They're cheap and easy to find especially in the case of a Bosch model like ours. Alternately, GM's version this component is an excellent choice.
5. Tachometer
A failing engine sensor could cause a variety of issues in your car. It's an essential component of the transmission in your Audi, as it transmits information to the ECU on how fast or slow the engine of the car is turning. If this sensor fails, it can affect the performance of 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 sends a signal directly to the ECU at pin T55/49 through an uncolored wire. The ECU is then able to process this signal to regulate fuel, timig, and boost and then transmitting it to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see around 1000 ohms of resistance between these two points. new audi key is the same across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 Du So, you may find good ones in wrecking yards.