Ok, I have been struggling with a few things on my car. My ABS is playing funny tricks, my cat is showing a 420 code and I have a headlight that keeps turing off. I also noticed that as my ABS engages on dry ground and my stopping gets worse as my peddle shudders, my dash lights also flickered on and off. I also notice this as I go over bumps every once in a while and if I have my headlights on and I move my front seat to an extreme the power seat will dim the lights in the car.

I would like to trouble shoot all of this and replace only the thing I need to replace if they are all related rather than replace everything only to find out that it was something like a negative battery cable.

I had the battery and Alternator checked at AutoZone and they said they were all in working order. I am sure it is not the correct battery, however, they said it had more than enough amps for the car. What do you all think? Could all this be related?

Thanks,

David

 

Dave,

Probably a loose connection or bad due to corrosion...I would first check all your Battery's NEG. ground points..Two major ones under the hood..One attached to the inner horizontal body wall, just behind the Left hand Headlight assy..and the other one is under the battery on top of the transmission. Any wires (usually black) you see attached by a bolt or screw to the car's body is a ground point and you should give them all a tightening snug......There also could be a loose connection of the Positive battery lead that is connected to the underside of the fuse box, also on the left side of the battery.

I don't believe it is a short as people like to think that is always the problem with electrical circuits...A short would usually blow fuses...And you didn't mention any of that happening.

 

I would be looking at the grounds between the cab of the vehicle and the battery. From what you describe, it is sounding like you have a bad cable that has gotten internal resistance and this is causing a voltage drop, resulting in the lights dimming and the computers to act funny.

I would say to start with starting up the car and turning on everything electrical that you can and then after a few minutes, running your hand over the battery cables. If the cable is starting to go bad, you will find that the cable will be very hot (should be somewhat warm, but I am talking "fry an egg on it hot"). If you find this, then replace the cable in question and see what you have then.

 

According to what he said..it is NOT a battery cable problem in the sense it has gone High resistance. I said it is more than likely a Loose connection or bad ground point to the car...Let's not steer him down so many paths at once..

 

Thanks DPK and Thermo,
I checked the connection and they were solid. While running the car with everything on the Negative cable was hot at the terminal. Positive was warm. Pulled the battery and box and replaced with two cables and a clamp from O'reilly Auto Parts.

While I was in there I noticed a red cable that ran to a clear plastic bubble bolted to the wheel well. I think it was to a Kicker Amp someone had previously installed in the car. The end was hanging loos and appears to go to the trunk where it was just cut off. I attached it to the negative cables and when I turned the car on the abs immediately came on. I took it off the negative cable and everything seems to be great. The next few days will tell.

BTW. With the new negative cables on after I ran the car they were still cool to the touch. Keep my fingers crossed. I wonder if that kicker cable was causing some kind of shorting.

Thanks for now everyone. You are awesome!!! Until next week when something else pops up.

David

 

Great news..thanks for the report back.

 

Thanks to you both for the help. Is it wrong to think that most of the things that happen with these cars has nothing to do with what the code reader is telling us? I am really grateful for all those of you who are fluent in Jaguar and can help discover what is really happening with our cars.

I will try to remember to report back in a week or so to let you know if this solved it all for good.

 

ddsand, it is very possible that if the old stereo cable was attached to the positive battery terminal and was also cut off in the trunk that you were actually grounding out the electrical system and overloading the alternator. This would cause the voltage to drop in the car, leading to the flickering lights that you were seeing. Due to the wire not maintaining contact for a long time, it wasn't enough to blow the heavy amperage fuse in the plastic bubble.

Personally, if you are not using that cable, pull it out of the car. It is only going to cause problems. But, it sounds like you had 2 issues, old cable making intermittent connection, leading to an overload of the alternator and then the second issue being the battery cables were not where they should have been in their ability to handle current. One compounded the issue with the other.

 

It is certainly a learning experience. I am glad we got the battery cable fixed. I still have not felt the abs kick in, however, the ABS warning light has kicked on. I guess I need to go back and check the sensor. I tried to get the screw out that holds it in. Is it an allen or torx and what size? Anyone know? Thanks. Again I have a c1155 code. I believe that is a left front sensor.

 

ddsand, yes, C1155 refers to the left hand, front wheel speed sensor. You can try getting a new sensor to see if that is it. I would also give the wiring a good look over just to make sure something didn't get caught up in the wheel and damage something. From there, if the sensor and the wiring doesn't fix things, then you are looking at a new wheel bearing.

 

Thermo, The wheel bearing does not sound bad. could it have just lost its magnetism and how common is that?

 

ddsand, the sensor will not loose its magnetism unless it is heated up extremely hot (ie, melt plastic hot). So, a simple look at the sensor will tell you if that has happened. As a general rule, there are only but a few things that can affect the speed sensor: speed, distance, or electrical pick-up. Since the distance is a given and can only be changed if you either install the wheel bearing backwards (been known to happen) or the sensor is not installed all the way. So, distance is a pretty easy one to figure out. Speed is what you are actually measuring, so, this is one that doesn't have a true "it can go bad". This leaves you with the electrical pick-up. This is where inspection of the wiring will normally show a problem (exposed copper or the wiring making a sudden bend indicating a broken wire inside the insulation). If you want to prove the sensor good, you can simply connect up a multimeter to the 2 pins on the sensor and set the multimeter on the 2VDC scale. From there, you can pass a large ferrous/metallic object (screwdriver is something easy and that is ferrous) near the sensor. This will cause the multimeter indication to jump as the screw driver passes by. The closer and faster that you move the screwdriver, the larger the indication will be. Using an analog meter or a digital meter with the "analog bar" on it makes this the easiest to see. This will prove things good/bad and help you eliminate things in the circuit.

 

Thanks Thermo,

I had seen a youtube video of someone checking with an ohm meter. I would like to remove the sensor and clean it, but am afraid I am stripping the screw. Is it an alan or a Torx? Also what size? Thank you so much for your help.

 

Ok, So i think I may have figured it out thanks to all of you. I was able to finally get a better look at the screw. it took a T25 Torx. I pulled it and it was a little dirty. I have cleaned and reinstalled and so far no problems. I will let you know if it comes back. Thanks for all your help Thermo and DPK.

 

You are very Welcome Buddy..glad I could help.

 

So almost 1 year late and I still have not fixed the problem. It is now getting a little worse. In my previous post I mentioned the headlight going out. (Nothing a Fonzie fist bump won't fix) and the P0420 code. The 420 code I finally fixed thanks to help on another post and finally getting off my lazy butt and changing out the o2 sensors. (Thank Heavens I do not have to replace the Cat) The last issue is this darn ABS code.

So, now that this is pretty much the last thing I need to do, I noticed the other night when i was braking that when the ABS went on my headlights dimmed. I am hoping that rules out a bad bearing or bad sensor. Probably the wires of the abs grounding on the body. Anyone have any other ideas before I tear into it?

Thank again for all the help everyone gives.

P.S. loved the car so much I bought a second one. I now own two 2003 jaguar x-types and unlike the MGBs I used to own, neither is a parts car and they both run.

 

ddsand, from what you are describing, your problem stems from a voltage fluctuation causing the ABS computer to have issues (computers hate changing voltages).

Have you checked the battery cables for any abnormalities? A quick check you can do is let the car sit over night so everything is ice cold. Now, start the car (letting it idle) and then turn on the dash fan on high, both seat heaters, rear defroster, and headlights. This should put a decent load on the electrical system. Now, cup your hand over the battery posts to see if they are at the same temperature as the engine bay or if they are hot (do not touch as they can get hot enough to burn yourself). If they are hot, then you have a bad battery cable and it needs to be replaced.

After this, you will need to hand over hand the wiring going to the ABS module to see if there may be any damage to it. May want to pull off the plug to the ABS module and make sure all the pins are silver in color (not a dull gray/brown). Granted, dirty pins would not cause the headlights to dim.

 

Thanks Thermo. This is the same car you had me check a while back and it had a hot Negative Battery Cable on it. I ended up replacing the manufacturers cable with two separate cables on a single mount. Since that time the negative cable has been cool. I will double check.

You mentioned checking the pins, I will see what I can find there. Should I look at the wheel or when it connects higher. I have looked for a diagram showing how those wires run from the drivers side wheel to the abs box. Is it one continuous wire or is there a connection somewhere once it goes through the wheel well?

Thanks

David

 

ddsand, looking at the diagrams, for the most part, the ABS harness is a stand alone piece. The only exceptions is the power wire coming from the fuse box in the dash and the 2 sets of wires going to the rear wheels (these have a plug near the firewall from what I can tell in addition to the plug near the wheel itself that the sensor plug into).

As for checking the pins, I would be looking more at the ABS module itself for problems. A problem at a wheel would give you completely different indications. Specifically, you are probably want to look at pins 24 and 40. These are the two that feed the information back to the ECU for processing and then sending on to the instrument cluster for speed indication.