How to Replace an audi key programmer G28 Engine Speed Sensor

In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is situated on the edge of the transmission above the flywheel ring gear. It transmits a signal the ECU via the grey wire (T55/49), then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated at the edges of the transmission, just above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indicator to the G5 Tachometer within the instrument cluster.

The sensor is used to link the G40 Camshaft position Sensor. The ecu must be aware of when the crankshaft has reached TDC, and the location of the camshaft to trigger the spark and injectors.

If this sensor fails when it fails, the ECU will display an error code P00160. 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 timing chain. The code won't appear without the additional information provided by other sensors (G4 or G40).

It can be a bit difficult to test as there are different pins on the connector, and each one has different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is in full operation. Check for signs of coolant, or oil in the connector bay if you are experiencing problems with this part.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll i had a big cut in power like the engine is out of gas or injectors aren't firing at all. This morning i pull out the spark plugs. Three were drenched in gazoline, the fourth one was dry. I put tissue over each injector hole and when I start the engine with no sparks, the ones that have gazoline pop right out. The fourth one remains shut. I checked the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I assume that the problem is elsewhere.

I also tried to reset the PID without success. The car will start when the G28 is unplugged, and programmers it works fine when the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows an ice temperature of -49c. I also noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 when i rev the engine.

I'm not certain what to do, as i believe that i've completely ruled out all other possibilities. However, i'm afraid that I might have missed something. Let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump of the g28 receives signals from the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or parts store. Test them out to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's end). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to know both the position and speed the crankshaft to determine timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either of these sensors, the diagnostic scanner will display codes that could cause an engine shut down.

A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter and Replacement audi a3 key (https://autolocksmiths51454.bcbloggers.com/29199670/it-s-enough-15-things-About-audi-keys-we-re-overheard) a gearbox which shifts more quickly than normal, audi tt key programming and/or a misfire while in the gear. It is possible that the sensor is failing and needs to be replaced if you encounter any of these signs. The good news is they are very cheap and easily accessible particularly in the case of an Bosch sensor, like ours. Alternately, the GM version of this part is also a great option.

5. Tachometer

A faulty engine speed sensor could be the reason behind numerous problems in your car. It's an essential component of the transmission in your audi key fob not working since it sends information to the ECU on how fast or slow the engine of the car is turning. This sensor could cause the transmission to fail and other components of the car to be affected.

The G5 engine speed sensor is located on the edge 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 this signal to regulate fuel, timig and boost, and also transmitting it to the G5 tachometer inside the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see an average resistance of 1000 ohms in these areas. This is the same across the audi replacement key service 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du, so you might find them in wrecking yards.