The 10 Most Infuriating Audi G28 FAILS Of All Time Could Have Been Avoided
The 10 Most Infuriating Audi G28 FAILS Of All Time Could Have Been Avoided
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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 on the outside of the transmission over the flywheel gear. It sends a message to the ECU through the grey wire T55/49 and 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 an uncolored wire. The ECU then uses this information to control fuel, timig and boost. It also sends signals to the G5 tachometer inside the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors according to the situation.
If this sensor fails, the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync, possibly indicating 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 can be a bit difficult since there are two connector pins and they have different functions but the most effective way to test it is to measure resistance between the sensor and the ECU. When the sensor is fully functional, it should read around 1000 ohms. If you're having issues with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at maximum speed, i noticed a huge reduction in power. It was as if the engine had run out of gas. Or, my injectors weren't firing. In the morning, i removed the spark plugs, three were drenched in gazoline, the fourth was dry. I put a piece of tissue over each injector hole, and when I start the engine with no sparks, the ones with gazoline jump right out. The fourth one remains closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero ohm. I assume that the problem is somewhere else.
I also tried to reset the PID but with no luck. The car is able to start if the G28 is not plugged in and it runs perfectly when it is plugged in, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows website an ice temperature of -49c. Also, i noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when i rev the engine.
I don't know what to do. here I feel like i've pretty much all other possibilities out. I'm worried that i might have missed something. If anyone has any ideas please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals 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 from a parts store. It is simple to test them - simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines replacement audi car key are equipped with an ECU that has to be aware of the speed and position of the crankshaft to make decisions about timing of the fuel injector, for example. In order to do this it uses 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 cause an engine shutdown.
A damaged G28 sensor can cause an inaccurate speed counter for your gearbox or a gearbox that shifts more quickly than normal, or a misfire while in the gear. If you experience any of these issues it is likely your sensor is deteriorating and should be replaced. The good news is they are very cheap and easy to find, especially if you're looking at a Bosch unit which is what ours are. You can also choose the GM version of this unit is also a good option.
5. Tachometer
A failing engine speed sensor could be the cause of many issues with your car. It is a crucial part of the Audi's transmission because it communicates to the ECU about how the car's crankshaft is spinning. When this sensor fails, it will affect the performance of the transmission and the other car's components.
The G5 engine speed sensor is located at the edge of the transmission just above the flywheel ring gear. It sends a signal to the ECU at pin T55/49, via a grey wire. The ECU then uses and processes the signal to control the flow of fuel, timig and boost as well as transmitting it to the G5 tachometer in get more info the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. Additionally, you can verify continuity between pin 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 around 1000 ohms of resistance between those two pins. This is a standard component across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good ones might check here be availble in wrecking yards.