What behavior would a 5.3 swap with a failing Land Rover CPS exhibit? Out of curiosity....

 

Update.

After work I decided to fiddle with the truck a bit. Previously I only had only 1 ground coming off the battery going to the alternator bracket.

I decided to add another ground from the battery to a stud behind the driver headlight.

Reconnected everything and went for a long drive. No more issues.

I'll update over the next few days if this actually fixed everything.

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Good to know you think you found your issue. Bad/inconsistent ground would make a lot of sense. Will add to post above as something to check if that is the problem.

Just for reference, the bad Rover CKP sensor would have main symptoms of the M/S lights (F_N_MOT code), no / inconsistent tach signal, fuel pressure issues (possible no start or start and die)

 

Thank you both for these posts. Wondering if that is my issue as well. My symptoms a little different in that the Hill decent, traction control and M&S lights come on consistently only when I turn on the AC/HVAC. If I leave the HVAC off, no warning lights come on. With warning lights illuminated, turn HVAC off and restart the engine. Lights will go off. Engine functions perfectly no issues starting running etc. RPM showing normal.
This did work previously (no warning lights). After fan shroud install adjustment to some of the wiring this issue started occurring.
- Replaced the CPK just to make sure that wasn’t issue
- Disconnected plugs for the electric fans (radiator). Issue still occurs.
- Increased idle to 800 then 850. No change (thought maybe it was dip in idle speed)

Appreciate any help.
here are some screen shots. Sorry for taking up the forums storage space..

 

Run a ground from the battery to the factory ground location right behind the headlight on the sheet metal.

 

The T_ANS and MD_IND are from not running the MAF. On their own, I do not believe they will cause the M/S lights.

WFPDK is TPS system and related circuit. Since your problem is only when the A/C, my guess is the A/C is causing a voltage/current drain. New ground like Boostle says may help. I’d also check the ground from the battery to the engine block - if it is not a solid point it can cause a bunch of issues. Have also heard of adding additional ground from block to body.

 

Another thing I noticed was that previous to adding the ground my voltage would be around 13.6-13.9 with the fans on. After adding the ground it consistently stayed above 14.

 

Thank you Boostle and CaptainAaron. I’ll get those things done and cross fingers!

 

I took a 4 hour round trip drive this weekend. No more lights. Looks like bad/insufficient grounding caused my issues.

 

Good to hear, will add to post above.