Error Codes 'Eng 24' 'AT 23'

Hot_aces · Post by **Hot_aces** » Sun Jan 11, 2009 1:46 am

Hi All,

Now and again my car goes into Limp Mode so I have just done a diagnostics test and got the following error codes:

Engine Code 24 - Vehicle Speed Sensor
Auto Trans Code 23 - Output Shaft Speed Sensor

Can anyone tell me if it is easy and how to replace these parts.

Also as the faults seem to be intermittent is it likely to be problem parts that work sometimes or is it likely to be wiring and grounding issues, how do you find out.

TIA
1997 GX 5 Speed Auto

Storm · Post by **Storm** » Tue Jan 13, 2009 9:31 pm

Out put speed sensor is easy to replace, sits on the back of the gearbox. If it doesn't match up with the reading from the input, taking into account what gear you are in, it will put the car into limp mode so saving the box from damage if possible.

The sensor can get dirty and have an intermitant fault but this usually means it is going to fail anyway so you should just replace it.

Bill

Hot_aces · Post by **Hot_aces** » Wed Jan 14, 2009 7:55 pm

Thanks for the reply Bill.

Do i have to remove any other mechanics to get at the Output Sensor or is it easily accessable.

Also read in one of the manuals that if the signal from the Output Sensor reads slower than the Vehicle Speed Sensor on 4 occassions then limp mode will be activated. As my speedo has been jumping upto 180 sometimes this could lead the ECU to give an error code for the Output Sensor when the real problem is with the Vehicle Speed Sensor.

As I have 2 error codes it is difficult to know which to change 1st. I think I am going to change the Converter Chip 1st as this can be associated with problems with the Vehicle Speed Sensor and is also the cheapest place to start.

I will keep this thread updated but if anyone has other thoughts please let me know.

I would be grateful if someone could post a pic of the Output Sensor and Vehicle Speed Sensor showing their positions in the engine bay.

Hot_aces · Post by **Hot_aces** » Wed Jan 21, 2009 9:05 pm

Just a quick update.

Although i got the error code for the Output Shaft Speed Sensor (Engine code 24) this was a false reading caused by the problems with the Vehicle Speed Sensor (AT Code 23).

As the ECU was reading speeds upto 180MPH when really only doing 30MPH it assumed the 180MPH was correct (I wish) and that the problem was with the Output Shaft Speed Sensor not reading correctly. However the Output Shaft Speed Sensor was OK and it was the signal from the Vehicle Speed Sensor causing the problem.

In my case the the problem was solved by changing the Converter Chip which was the cause of the erractic signal.

Hope this proves helpful to other FTO owners.

1997 GX 5 Speed Auto