The Reasons To Focus On Making Improvements In Audi G28

How to Replace an audi advanced key G28 Engine Speed Sensor

Charles the Humble Technician teaches you 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 transmits a signal to the ECU via the grey wire (T55/49) and then to the tachometer in 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 a signal to ECU pin T55/49 via a grey wire. The ECU utilizes this information to regulate boost and fuel. It also sends an indication to the G5 Tachometer in instrument cluster.

The sensor is used as a reference to correlate with 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 start spark and injectors in the right way.

If this sensor fails the ECU will display a P00160 code which means 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 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 most effective method to test it is to measure resistance between the sensor and the ECU. If the sensor is operational, it should be reading approximately 1000 ohms. Check for signs of coolant, or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at full speed, i noticed a huge reduction in power. It was as if the engine was running out of gas. Or, my injectors were not firing. I pulled out the spark plugs this morning, 3 were soaked in gasoline, and the fourth was dry. I put a piece of tissue over each injector hole, and when i turn the engine on without sparks, the ones with gazoline jump out. The 4th one stays shut. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I got 0ohm. I assume that the problem is somewhere else.

I also tried to reset the PID without success. The car is able to start when the G28 is unplugged and it runs perfectly when it is plugged in but it still has the intermittent misfire issue at higher RPM. The coolant sensor (G62) even when it is unplugged, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.

I don't know what to do. I feel like i've pretty much all other possibilities out. But i'm worried that I may have missed something. If anyone has suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is identical to the G4 and both function in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or at a parts store. It is simple to test them - just put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know both the speed and position of the crankshaft to make decisions regarding fuel injector timing, etc. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go wrong, you will receive codes on the diagnostic scanner that can cause the engine to shut down.

Some of the signs of a failing G28 sensor include an inaccurate gearbox rev counter and gears that shift faster than normal and/or misfiring when in gear. If you experience any of these issues it is likely that your sensor is deteriorating and requires replacement. They're inexpensive and easy to locate especially when they're a Bosch sensor like ours. Alternately, the GM version of this part is also a good choice.

5. Tachometer

A malfunctioning engine speed sensor could be a cause for many problems in your vehicle. It's a vital component of the audi replacement key Service's transmission as it sends information to the ECU about how fast or slow the vehicle's crankshaft is spinning. This sensor could cause the transmission to malfunction and other components of the car to be affected.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU uses this signal to control the amount of fuel and boost, and also to timigrate. It also transmits it to the G5 Tachometer located in the instrument cluster. You can check 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]) and between T6a/1 and the instrument cluster pin T26a/12. It should show approximately 1000 ohms resistance between those points. This is a common feature across the audi a1 key 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS AN and reprogrammed the 1995 RS2 DU, so you might find some good ones in wrecking yards.