4 Dirty Little Secrets About Audi G28 Industry Audi G28 Industry
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. The sensor is situated at the top of the transmission just above the flywheel ring gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using a grey wire. The ECU utilizes this information to regulate boost and fuel. It also sends an indication to the G5 tachometer inside the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to 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 the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and possibly indicating chain stretch or a jumped link on the upper timing chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit challenging because there are two connector pins and they serve different purposes but the most effective way to test it is to measure the resistance between the sensor and the ECU. When the sensor is functional, it should read around 1000 ohms. Check for evidence of coolant or oil in the connector bay if there are problems with this part.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at a high speed, i noticed a huge decrease in power. It was as if the engine had run out of gas. Or, my injectors were not firing. I took out the spark plugs this morning, three were drenched in gasoline and the fourth was dry. When I crank the engine, there are no sparks, I put a piece of tissue on the top of each of the injector holes, the 3 drenched with gazoline leap out, however the 4th one stays closed. I tested the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. I assume that the problem is somewhere else.
I also tried to reset the PID without success. The car can start when the G28 is not plugged in and it runs perfectly when it is connected but it still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62) even when unplugged, still shows an ice temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar while the actual pressure is 0.0 when i rev the engine.
I'm not certain what to do, i believe that i've completely ruled out all other possibilities. I'm afraid i may have missed something. If anyone has any suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The GM-style sensor is identical to the G4 and they both work in the 80, 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or in a local parts store. Test them out to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's end). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know both the position and speed of the crankshaft to determine timing of the fuel injector, etc. audi a1 key replacement utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these sensors go wrong, you will receive codes on the diagnostic scanner which could cause engine shut down.
Some of the symptoms of a malfunctioning G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or misfiring when in gear. It is probable that your sensor is failing and requires to be replaced if you experience any of these signs. They're cheap and easy to find, especially in the case of an Bosch sensor like ours. Alternately, GM's version this part is a good option.
5. Tachometer
A malfunctioning engine speed sensor could be the reason behind numerous issues in your car. It's an essential component of the transmission of your Audi, as it transmits information to the ECU about how fast or slow the engine of the car is spinning. When this sensor fails, it could affect the performance of the transmission and the rest of the car's components.
The G5 engine speed sensor is situated on the edge of the transmission just above the flywheel ring gear. It sends a signal to the ECU at pin T55/49 through a grey wire. The ECU then uses and processes this signal to control fuel, timig, and boost and then sends it on to the G5 tachometer in the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see an average resistance of 1000 ohms between these two points. This is a standard part that is found across the Audi 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good parts could be found in wrecking yards.