Why Nobody Cares About Audi G28

How to Replace an audi key fob G28 Engine Speed Sensor

Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. This sensor is situated near the transmission's edge over the flywheel 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, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through the grey wire. The ECU utilizes this information to regulate the amount of fuel and boost. It also sends an indicator to the G5 Tachometer in instrument cluster.

The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu has to be aware of when the crankshaft has reached TDC, and the location of the camshaft in order to activate the spark and injectors.

If this sensor fails when it fails, the ECU will display a P00160 error message. This means that the Crank Shaft is out of alignment with the Intake Camshaft. It could also indicate an issue with the chain or a jump in the chain link of the upper timing chain. However the code will not appear on its own without additional information from other sensors (G4 and G40).

Testing is a bit tricky as there are two different connector pins and they serve different purposes however the best method to test it is to measure resistance between the sensor and the ECU. It should read about 1000 ohms if the sensor is operating at its maximum. Check for evidence of coolant or oil in the connector bay if there are issues with this component.

2. Injectors

Yesterday, while accelerating from the highway paytoll at maximum speed I noticed a significant decrease in power. It was as if the engine was running out of gas. Or my injectors weren't firing. I took out the spark plugs this morning, 3 were soaked in gasoline, and the 4th was dry. When I start the engine without sparks, i place a tissue on the top of each of the injector holes and the 3 drenched with gazoline pop out, but the 4th stay closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found 0ohm. I assume that the problem is elsewhere.

I also tried to reset the PID but without success. The car will start when the G28 is unplugged and it runs perfectly when it is plugged in however it has the intermittent misfire issue at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c even when i unplug it. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar while the actual pressure is 0.0 if i crank up the engine.

I'm not certain what to do, but i feel i have pretty much ruled out everything else. I'm afraid i may have missed something. Please let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump in 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 which is why you can easily locate one at a wrecking yard or at a parts store. It is simple to test them: simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). They should 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 fuel injector timing, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these, the diagnostic scanner will show codes that could cause an engine shutdown.

A failing G28 sensor could cause an inaccurate gearbox speed counter or a gearbox that shifts faster than normal, or a misfire while in gear. If you have any of these problems, it is likely your sensor is going bad and should be replaced. They're cheap and easy to find particularly when they're an Bosch sensor like ours. If you prefer, GM's version of this part would be an option.

5. Tachometer

A malfunctioning engine speed sensor could be the reason behind many issues with your car. It is an important part of the transmission of your audi key since it sends information to the ECU on how fast or slowly the engine is turning. This sensor could cause the transmission to fail and other car components to be affected.

The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It sends an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to regulate fuel and boost, and also timig. It also transmits it to the G5 Tachometer in 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 [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see the resistance to be around 1000 ohms in these areas. This is a common feature across the audi key programmer tt replacement audi keys key (redirected here) 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 Du So, you may find some good ones in wrecking yards.