(Image: https://g28carkeys.co.uk/wp-content/uploads/2023/10/honda-logo.png)How to Replace an audi a1 key 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 the ECU via an uncolored wire (T55/49), then to the tachometer within 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 signals to ECU pin T55/49 using an uncolored wire. The ECU utilizes this information to regulate boost and fuel. It also sends an indication to the G5 tachometer inside 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 location 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 chain of timing. The code won't show without the additional information supplied by other sensors (G4 or G40).
It can be a bit difficult to test as there are several 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 approximately 1000 ohms when it is operating at its maximum. Examine for signs of coolant, or oil in the connector bay if you have issues with this component.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at a high speed I noticed a significant drop in power. It was as if the engine was running out of gas. Or my injectors were not firing. In the morning, i removed the spark plugs, three were drenched in gazoline, the fourth was dry. When i crank the engine with no sparks i put tissue on the top of each of the injector holes and the 3 drenched with gazoline jump out but the 4th one stays closed. I checked the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I assume that the problem is somewhere else.
I also tried to reset the PID but with no luck. The car key cover audi is able to start if the G28 is unplugged and it runs perfectly when it is connected, but still is experiencing intermittent misfires at higher RPM. The coolant temperature sensor audi Key Copy (G62) shows the wrong temperature of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.
I'm not sure what to do. I believe that I've all other possibilities out. But i'm worried that I may have missed something. If anyone has any ideas please chime in! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. The GM-style sensor 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 salvage 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 at the connector end facing up). They must be infinite ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines needs to be aware of 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 bad you will get codes on the diagnostic scanner that can lead to engine shutdown.
Some of the symptoms of a failed G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal, and/or a misfire when in gear. It is likely that the sensor is failing and needs to be replaced if you notice any of these symptoms. They're inexpensive and easy to locate especially in the case of a Bosch sensor like ours. Alternately, the GM version of this component is also a great option.
5. Tachometer
A failing engine speed sensor could be a cause for many problems in your vehicle. It is a crucial part of your audi car keys's transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is rotating. This sensor can cause the transmission to fail and other car components to be affected.
(Image: https://g28carkeys.co.uk/wp-content/uploads/2023/10/renault-logo-evolution.jpg)The G5 engine speed sensor is situated on the edge of the transmission above the flywheel ring gear and transmits a signal to the ECU at pin T55/49, via an uncolored wire. The ECU then uses and processes this signal to control the flow of fuel, timig and boost and then sends it on to the G5 tachometer inside the instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe approximately 1000 ohms of resistance between those two pins. This is a common part that is found across the audi smart key Replacement 80, 100 200, audi replacement key Fob UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.
