No communication with Module

[John Saint]

I am a new member from England. I have a Right Hand Drive Seville STS made in the US in January 1999. These cars were produced so that GM could attempt to enter the luxury car market here in the UK. I can only assume that this was unsuccessful as the few dealers who were appointed were abandoned after a short time, hence very little service back-up is available here. I purchased the car with 1000 miles on the clock, it has now records 20,000 miles, it has had very little summer only use.

I have always felt that the brakes on this car were below the standard that could be expected in a car of this performance and so I decided to look into the issue. Realising when I first acquired the car I would have to carry out myself many of the tasks usually confined to dealers, I purchased a new Tech 2 and the K series Service Manuals, 2 volumes.

Right Hand Drive cars are fitted with an extra component in the braking system, a Brake Booster Pump, which supplies hydraulic pressure to the system when the accumulator is discharged. By the tests shown in the Service manual, I established that the relay had failed and so the pump was not working. I replaced the relay; the old part number is obsolete but is replaced by an equivalent. The pump motor ran when the ignition was turned on although there was a good deal of ‘gurgling’ at first. There was a marginal improvement in braking.

I decided to see if there were any error codes. One showed up relating to the front left speed sensor. I expect this was the first time the system had been investigated since it was installed, there were lots of error codes for the engine relating to misfires etc, and so I decided to clear them all and run the car for a while to see what new codes appeared. After about 100 miles there was a chime and the dashboard lights for ABS and Traction Control came on.

I connected the Tech 2 to investigate but got the message for the Chassis section ‘no communication with the module’ although there was communication with the engine management system.

I don’t have a pin-out box yet or the proper Kent Moore adapter but I was able to follow, more or less accurately, the test sequence shown in the Service Manual for this condition, check fuses front and rear etc. There is battery voltage at the Electronic Brake and Traction Control Module. The ground is supposed to be 2 ohms but is nearer to zero.

At the same time as the dashboard lights came on the Brake Booster pump now makes a ticking noise when running although it functions in raising pressure and cuts out at the required level as normal.

I am not sure where to go from here. I hope it is not a failure of the Brake and Traction Control Module as it is a special one for Right Hand Drive cars and is very costly. I am not sure how to test that unit without communication from the Tech 2.

Any help or advice you can give would be invaluable and I thank you all most sincerely in advance.

Monty

[Bowler807]

Since you already stated that you have a wheel speed sensor code, that is where to start. The ABS system uses information from these sensors. If one is not reading, the system will display an ABS / Traction Control fault.

[John Saint]

Since you already stated that you have a wheel speed sensor code, that is where to start. The ABS system uses information from these sensors. If one is not reading, the system will display an ABS / Traction Control fault.

Hi and thanks for this helpful advice. Would a wheel speed sensor fault give the 'no communication with the module' on the Tech 2? When I first picked up the code it was via the scanner which had communcation with all the chassis available data despite showing the error code.

Renewed thanks

Monty

[trevor]

Since you already stated that you have a wheel speed sensor code, that is where to start. The ABS system uses information from these sensors. If one is not reading, the system will display an ABS / Traction Control fault.

Hi and thanks for this helpful advice. Would a wheel speed sensor fault give the 'no communication with the module' on the Tech 2? When I first picked up the code it was via the scanner which had communcation with all the chassis available data despite showing the error code.

Renewed thanks

Monty

[trevor]

hi Monty I am a member in Australia with a 2000 right hand drive seville sts because of work commitments I dont very often spend time on this site also computers dont come easy for me. However this site was really helpful to me when i first bought this car. now i had exactly the same issue with that relay on the brakes . Like you at one stage I had multiple codes come up on this car which is pretty disconcerting on a trip there is no dealers here either. For whats its worth I went through every earth this car has and it has completely eliminated every code i ever had. LOts of them had signs of corrosion when i undid them. I think the earths on these cars is a lot more critical then we think maybe depending on the history of the car. Ialso have a 90 seville that i brought back from los angeles in the early 90s.Whenever the dash plays up on this its always been a earth problem .These cars are made too good to have inherent problems .Try it and tell us what you think regards Trevor

[John Saint]

hi Monty I am a member in Australia with a 2000 right hand drive seville sts because of work commitments I dont very often spend time on this site also computers dont come easy for me. However this site was really helpful to me when i first bought this car. now i had exactly the same issue with that relay on the brakes . Like you at one stage I had multiple codes come up on this car which is pretty disconcerting on a trip there is no dealers here either. For whats its worth I went through every earth this car has and it has completely eliminated every code i ever had. LOts of them had signs of corrosion when i undid them. I think the earths on these cars is a lot more critical then we think maybe depending on the history of the car. Ialso have a 90 seville that i brought back from los angeles in the early 90s.Whenever the dash plays up on this its always been a earth problem .These cars are made too good to have inherent problems .Try it and tell us what you think regards Trevor

[John Saint]

Hi Trevor,

Thanks for this encouraging reply. Since posting last time 2 things have happened. I have now got the factory Pin-Out Box and connector to carry out proper tests on the ABS system but, like you, time has prevented me doing so up to now. Secondly, I have been told by someone in the States, who has apparently worked on Cadillac diagnosis at the factory, that you can get a 'good' ground, or earth as we call it in the UK, with a test meter but that is not the same as what might happen when the circuit is under load. He recommends using a headlight bulb to put the circuit under load as would be the case in use, to test the circuits. I am about to start to do this. He also told that the ground is a major cause of apparent failures as your experience also suggests.

Thanks again for your helpful post.

Best wishes

Monty