How to Replace an audi replacement key service G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located on the outside of the transmission over the flywheel gear. It transmits a signal to the ECU via a grey wire T55/49, [Redirect-302] then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated at the edges of the transmission, directly above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU utilizes this information to control the amount of fuel and boost. It also sends signals to the G5 tachometer in the instrument cluster.

The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu has to be aware of when the crankshaft has reached TDC, and the position of the camshaft, in order to activate the spark and injectors.

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 the chain is stretched or a jump link on the upper timing chain. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).

It is a little tricky to test because there are several pins on the connector and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. When the sensor is operational, it should be reading about 1000 ohms. If you're having issues with this component, look for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, when accelerating from highway paytoll at a high speed I noticed a massive drop in power. It was as if the engine had run out of gas. Or my injectors weren't firing. Today, i pulled out the spark plugs. Three were drenched with gazoline the fourth one was dry. When I crank the engine without sparks, I put a piece of tissue on the top of each hole in the injector, the 3 drenched with gazoline leap out, however the 4th one stays shut. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 I get zero Ohm. Therefore, i think the issue is somewhere else.

I also tried to reset the PID without success. The car will start when the G28 is not plugged in and runs fine when it is plugged in, but still has the intermittent misfire issue at higher RPM. The coolant sensor (G62) even when it is unplugged, shows a temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar when the actual pressure is 0.0 if i crank up the engine.

I don't know what to do. I think I've ruled everything else out. But i'm worried that i might have missed something. Let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily locate a spare in a wrecking shop or a parts store. It is simple to test them to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's end). They must be infinite ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that must be aware of the speed and position of the crankshaft in order to make decisions regarding timing of the fuel injector, for example. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you encounter a problem with either of these sensors, the diagnostic scanner will show the codes that could trigger an engine shutdown.

The signs of a failed G28 sensor include 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 experience any of these issues it is most likely that your sensor is failing and needs replacing. They're cheap and easy to find especially in the case of an Bosch model like ours. You can also choose the GM version of this component is also a good choice.

5. Tachometer

A failing engine sensor could cause a number of problems in your vehicle. It is a crucial part of the audi spare key replacement key for audi a3 key service (this guy)'s transmission because it communicates to the ECU about how fast or [Redirect-302] slow the car's crankshaft is rotating. When this sensor fails, it can disrupt the performance of the transmission as well as the rest of the car's components.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It transmits signals via an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to control the amount of fuel and boost, and also timig. It also sends it to the G5 Tachometer in instrument cluster. You can test 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]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should detect an average resistance of 1000 ohms between these two points. This part is common across the Audi 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS AN and the 1995 RS2 Du, so you might find good ones in wrecking yards.