How to Replace an Audi G28 Engine Speed Sensor
In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is situated near the transmission's edge over the flywheel gear. It sends a signal to the ECU via a grey wire (T55/49) and then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through the grey wire. The ECU uses this information to control the amount of fuel and boost. It also sends an indication to the G5 tachometer inside the instrument cluster.
The sensor is used to link the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors in the right way.
If this sensor fails the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper timing chain. The code won't appear without the additional information provided by other sensors (G4 or G40).
Testing is a bit tricky as there are two different connector pins, and they serve different purposes but the most effective method to test it is to measure the resistance between the sensor and the ECU. It should read about 1000 ohms when it is at full operation. Check for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll i had massive power loss as if the engine was running out of gas or the injectors are not firing at all. I took out the spark plugs this morning, 3 were soaked in gasoline, and the 4th was dry. I put tissue over each hole in the injector and when I turn the engine on without sparks, the three with gazoline jump right out. The fourth one remains shut. I checked the ground connection of ECU pins 14,30 and 48/55. I found zero ohm. I'm assuming the issue is elsewhere.
I also tried to reset the PID but without success. The car is able to start if the G28 is not plugged in and is running fine when it is connected, but still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when unplugged, still shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.
I'm not sure what to do, i think i've pretty much eliminated everything else. I'm concerned that i may have missed something. If anyone has suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump of the g28 receives here signals from the RPM sensor. The GM-style transmitter is identical to the G4 and they both work in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or in a local parts store. It is easy to test them: simply switch your DMM into audi key replacement near me resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to know the speed and position of the crankshaft to make a decision about timing of the fuel injector, for example. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these sensors, the diagnostic scanner will display codes that could cause an engine shutdown.
Some of the symptoms of a malfunctioning G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or a misfire when you're in gear. If you are experiencing any of these issues, it is likely that your audi keys replacement sensor is failing and needs replacing. They are cheap and easy-to-find, especially when they're an Bosch sensor like ours. You can also choose the GM version of this unit is also a good option.
5. Tachometer
A malfunctioning engine speed sensor could be the reason behind a slew of issues in your car. It's an essential component of the Audi's transmission since it relays information to the ECU about how fast or slow the car's crankshaft is turning. If this sensor fails, it could cause problems for the click here transmission and the rest of the car's components.
The G5 engine speed sensor is situated on the outside of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49, via an uncolored wire. The ECU then processes this signal to control fuel, timig and boost, and also sends it on to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by checking continuity from the sensor to the tachometer. Additionally, you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]) and between pin T6a/1 as well as pin T26a/12. It should show around lost audi key 1000 ohms of resistance between those two pins. This is a standard part across the Audi 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good parts could be found in wrecking yards.