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How to Replace an audi smart Key replacement G28 Engine Speed Sensor

In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located at the top of the transmission above the flywheel ring gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer in the instrument cluster.

image1. Engine Speed Sensor

The grey wire is located on the outside of the transmission, directly above the flywheel ring. The sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an alert to the G5 Tachometer within 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 activate spark and injectors in the right way.

If this sensor fails, prices the ECU will display a P00160 error code. This means that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of a chain stretch or a jumpy chain link in the upper chain of timing. The code won't show without the additional information provided by other sensors (G4 or G40).

Testing is a bit tricky because there are two connector pins, and they serve different purposes however the best method of testing it is by measuring resistance between the sensor and the ECU. It should read about 1000 ohms if the sensor is at full operation. Look for signs of coolant or oil in the connector bay if there are problems with this part.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced massive power loss as if the engine was running out of gas or the injectors aren't firing at all. I took out the spark plugs this morning, three were soaked with gasoline and the fourth was dry. I put tissue over each injector hole, and when I turn the engine on without sparks, the 3 with gazoline jump out. The fourth one remains closed. I tested the ground connection of ECU pins 14,30 and 48/55. I found 0ohm. I'm assuming that the issue is in another location.

I also tried to reset the PID but with no luck. The car is able to start when the G28 is not plugged in and is running fine when it is plugged in, but still has intermittent misfire issues at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature of -49c even when i unplug it. Also i noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.

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

image3. Fuel Pump

The fuel pump on the g28 is activated by a signal by the RPM sensor. The GM-style sender is the same as the G4 and they both work in the 80 100, 200, UrS and RS2 cars so you can easily find one at a wrecking yard or in a local parts store. It is simple to test them: simply 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 must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines needs to know the position and speed of the crankshaft to determine timing of the fuel injector, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go badly, you will see codes on the diagnostic scanner which can lead to engine shutdown.

Some of the signs of a malfunctioning G28 sensor are an inaccurate rev counter for the gearbox and gears that shift faster than normal and/or a misfire when you are in gear. If you are experiencing any of these issues it is most likely that your sensor is going bad and needs replacing. They are cheap and easy-to-find especially in the case of a Bosch sensor like ours. Alternately, GM's version this part is an option.

5. Tachometer

A malfunctioning engine sensor can cause a number of problems in your car. It is an important part of the transmission of your audi key replacement near me because it relays information to the ECU about how fast or slowly the engine is turning. This sensor could cause the transmission to fail and Audi Key Programming other components in the car to be affected.

The G5 engine speed sensor is located on the outside of the transmission, above the flywheel ring gear and sends a signal to the ECU at pin T55/49 through a grey wire. The ECU uses this signal to regulate the flow of fuel and boost as well as timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can check the sensor replacement key for audi a4 failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. It should show approximately 1000 ohms of resistance between these two points. This is a common feature across the audi advance key 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 DU, so you might find them in wrecking yards.

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