I have been having problems with Restricted performance since owning the car, It is currently off road having some renovation done, I have been looking for the reason for the traction control fail , stability control fail and ABS light being on.

What I have done so far is re-solder the ABS unit and I have replaced all the wheel sensors with new ones, all the plugs on the wheel sensors have been cleaned with electrical cleaner and still the faults won't go away, is there a specific way to clear the faults, does the car have to be driven to clear them, nothing is showing on my OBD11 reader

So, where to next, what else can I try

 

Yes, you have to drive the car to clear them.

 

Error codes are
P1637 = CAN Link ECM/ABSCM Circuit/Network Malfunction
P1720 = Vehicle Speed (Meter) Circuit

 

Those codes may have been the result of a weak battery in the past. I would clear them and see if they come back.

 

I have fitted a new battery and cleared the faults, also done a hard reset, which is basically disconnecting the battery again, the P1720 has cleared just leaving me with the P1637, CAN Link ECM/ABSCM Circuit/Network Malfunction

 

Need some help from someone more familiar with sedans. A possible cause of that and the P1720 is failure of speed input data from one of the rear wheel sensors. I don't remember which one, but a bad connection or broken cable could be the problem.

So which wheel is it guys?

 

Have you checked for continuity of the cable harnesses?
Is a quite straight forward procedure, good to tick off at least.
It's in the jaguar pdf manual.



Abs harness numbers for checking continuity and voltage



Checking the abs harness

 

I'll do that now, I've just printed the drawing off, so I can check the sensors and brake pedal switch and the earths

I have now got rid of all the error codes, the P1720 was probably a weak battery in the past as RJ237 said, and the P1637 was the scanner I was using at the time, I am now using my laptop and the fault has gone, So I am just left with:-

ABS Light is ON
Seat Belt light is ON
Orange light on dashboard ?
Traction Control Fail
Stability Control Fail

 

• Pins 3-4 RH Front Wheel Speed Sensor 1.119 Ohms
• Pins 6-7 RH Rear Wheel Speed Sensor 1.111 Ohms
• Pins 17-18 LH Front Wheel Speed Sensor 1.109 Ohms
• Pins 21-22 LH Rear Wheel Speed Sensor 1.114 Ohms

So all looks good on the wheel sensors

• 8 and 24 Show good ground connection
• Pin 2-Ground --------------------- 0.625 M Ohms constantly, regardless of Brake pedal position

Now to trace out the brake pedal switch

 

I have now found the switch, I thought it was the accelerator pedal switch but I found it and tested it, all is working on the switch.

There are two contacts and they both switch, I have stripped and cleaned the switch, refitted and tested again

It looks like its the outer two connections on the switch Orange/White comes from the ignition and Blue/Slate which goes to the ABS unit.

The cable between the Brake pedal switch and the ABS unit tests out okay.

So the problem must be between the Brake pedal switch and ignition switch or the ignition switch and ground.

 

Ignition switch has failed, I've taken it to bits to clean and found that it only has two springs on the back of the contacts, not sure how but who knows with the boy racer that had the car before me, anything is possible, the switch should have 3 springs on the back of each contact point, a new switch has been ordered so testing will resume once the part arrives

 

The car was like this when I bought it last year, its on the drive and is a side project so I am not working on it all the time, only between other jobs, it was a known issue, so no come back on the seller, the car is SORN so no test driving

So, this is what I have done so far to diagnose the fault

• New battery has been fitted and is fully charged
  • Yuasa 019
  • 95 Ah and 850 CCA
  • 12.5 volts standing voltage
  • 13.6 volts, charging voltage
• New wheel sensors have been fitted to all wheels and checked back to the ABS unit, two of the old front ones were no good, I ended up drilling them out but thought I would replace them all with new, new readings at the ABS unit are
  • Pins 3-4 RH Front Wheel Speed Sensor 1.119 Ohms
  • Pins 6-7 RH Rear Wheel Speed Sensor 1.111 Ohms
  • Pins 17-18 LH Front Wheel Speed Sensor 1.109 Ohms
  • Pins 21-22 LH Rear Wheel Speed Sensor 1.114 Ohms
• ABS unit pins to ground tested 8 and 24 show good ground connection
• The brake pedal switch has been removed cleaned and refitted, this is working fine
• The ignition switch was faulty, this has now been replaced Orange/White connection was bad, but now with a new switch I can test the connection through to pin 2 on the ABS unit
• The ABS unit has been removed and re-soldered, Looks like there was a dry joint
• Throttle body connections have been checked and cleaned

NOW –
Traction Control Fail has CLEARED
Stability Control Fail has CLEARED

BUT
ABS warning light is STILL ON

Any thoughts on where to go now, there are no OBD II Codes

 

You can't drive it so the ABS light won't clear.

 

What DTC(s) is/are logged in the ABS module??? (not the engine module).

We are all still guessing.

bob

 

Yes,Bob, and probably will be until he either gets a proper reader or has it towed to a shop.