How to Replace an audi replacement key G28 Engine Speed Sensor
Charles the Humble Technician shows you 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 via an uncolored wire T55/49, then to the tachometer 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 uses this information to control boost and fuel. It also sends a signal to the G5 tachometer in the instrument cluster.
The sensor is used to link the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can start spark and injectors accordingly.
If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is not in line with the Intake Camshaft. It could also indicate an issue with the chain or a jumpy chain link in the upper chain of timing. The code won’t appear without the additional information supplied by other sensors (G4 or G40).
It is a little tricky to test because there are several pins on the connector and they all have different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. When the sensor is fully operational, it should read about 1000 ohms. Examine for signs 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 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. I took out the spark plugs this morning, three were soaked with gasoline and the fourth was dry. When i crank the engine without sparks i put tissue on top of each injector hole, the 3 drenched with gazoline pop out, but the 4th stay closed. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero ohm. I’m assuming the issue is somewhere else.
I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it runs fine with the G28 connected. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62), even when it is unplugged, shows an ice temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when I crank up the engine.
I don’t know what to do. I think I’ve all other possibilities out. I’m worried that i might have missed something. If anyone has suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate a spare in a wrecking shop or parts store. It is easy to test them – just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector’s edge facing up). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines must know both the speed and position of the crankshaft to make decisions regarding fuel injector timing, etc. To do this, it utilizes 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 show codes that could cause an engine shut down.
Some of the signs of a failed G28 sensor include an inaccurate rev counter in the gearbox and gears that shift faster than normal and/or a misfire when you are in gear. If you have any of these problems, it is likely your sensor is failing and should be replaced. The good thing is that they are quite affordable and easy to find, especially when you’re looking at the Bosch unit which is what ours are. Alternately, GM’s version this part is an excellent choice.
5. Tachometer
A failing engine speed sensor could be the cause of numerous issues with your car. It is a crucial part of the replacement audi replacement key cost a3 key [carlocksmith09185.wikilinksnews.com]’s transmission since it relays 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 speed sensor is located on the outside of the transmission above the flywheel ring gear. It transmits 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, and also transmitting it to the G5 tachometer in the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. You can also examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. You should detect the resistance to be around 1000 ohms between these points. This is a typical part across the audi key replacement 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good parts could be found in wrecking yards.
