This forum always comes through but thought i would sweeten the pot a bit...

• The car does not crank
• The battery is good and I put a jumper battery on it also
• The starter is good, when I bypass the relay the starter cranks
  • When I turn on the ignition and then crank the starter directly from the relay, the car does not catch
• The OBDII codes I get are
  • P1251 Throttle Position
  • P0444 - Evap control valve valve open
• I have been doing some work that could have screwed up the electrical - messing with the audio, but nothing I did is obviously creating an issue
• I checked every fuse in the car

Let the ideas commence - the one that leads to solving the issue gets to pick a charity and ba boom, it will have a massive sum of $50 towards its mission....


When it is solved I will edit this fist post closing down the fun....

 

I found this thread. This person seems to have had good luck with the throttle relay being the culprit for the P1251 code. Hopefully it helps. Good Luck!!!

https://forums.jag-lovers.com/t/xk8-...d-p1657/249539

 

would the throttle relay lead to the car not cranking? I am thinking that the no start is not related to the codes but I am not sure where to look next.

 

The things that have bit me in other cars when they would not crank was the Park/Neutural interlock switch, or something in the ignition switch. Neither of them should keep the car from running after the starter relay was bypassed.

What did you have apart while messing with the audio?

 

The last step I did was i cut a bit of metal from the stand that the old amp and convertible hydraulic pump is on. Some dust from the grinder did spread around so I thought maybe some got onto the battery terminal or something that created a short in something but nothing is popping out as obvious to me.

 

A P1251 won't prevent the car from cranking.

It could be an issue with the rotary switch as Stogie25 notes (try starting in neutral), but there's more going on here so you can't eliminate the ignition switch at this point. The BPM ground signal to the starter relay is also fed back to the ECM, and this doesn't happen if the relay is simply bypassed.

You should be able to to get to the starter relay connections (in the RHS bulkhead compartment). Try grounding the Green/Orange wire - with the relay in place & ignition on - to simulate the BPM's action and report back what happens.

 

Michael,

We are getting somewhere. When I grounded the Green Orange the car cranked but did not start. I may have flooded the engine, mine is prone to that so I will take out the plugs and see if I can clean it out and start it.

That being said, do you have thoughts on what to do next, is my ECM trashed?

 

So i took out the plugs on one bank and there was no flooding. i still blew it out to make sure and cleaned the plugs but no go. I checked the fuel pump and got a good spray of gas so that is not the issue.

 

TBH that check was more curiosity on my part as it doesn't really prove much other than that (i) the BPM isn't outputting the ground signal to the starter relay and (ii) the relay and the power to its energiser coil is working OK.
I wondered if the car might start if everything else was in order other than the ignition switch. It may be that the BPM requires the ground input from that switch to respond properly.

There's quite a lot going on in the startup sequence. I saved this snip (4.0L cars) which I think is from one of the workshop manuals:

"
Passive Arming: Vehicles with Key Transponder Module (KTM)Engine cranking and starting are controlled by the ignition switch, ECM, BPM, P / N signal, key transponder module, ignition key reader exciter in the ignition switch, ignition key transponder and the gear selector not-in-park switch.

Cranking and starting are accomplished in the following manner:
Ignition key switched from the OFF position
• KTM receives a signal from the ignition switch position I as the key is turned
• KTM energizes the reader / exciter, which causes the key transponder to broadcast its security code
• If the key transponder code matches the programmed KTM code, the KTM outputs an OK TO START signal to the ECM via a serial data link
• ECM receives OK TO START signal and transmission P / N signal (hard wired from transmission), and enables fuelling and ignition
• ECM outputs a SECURITY ACKNOWLEDGE signal to the BPM via a serial data link
• BPM receives a park signal from the gear selector not-in-park switch and enables cranking if the security system has been disarmed
Ignition switch to position III (CRANK)
• Ignition position III crank signal is received by the BPM
• BPM grounds starter relay coil to energized starter motor
• ECM receives starter relay coil signal and sets engine starting values
"

It may be a security problem, but no sign of a P1260? Try one of your other keys.

Otherwise it's a case of eliminating any fault with the inputs to the modules, but the BPM isn't easy to get to. I'd start with the ignition switch -> BPM 'crank' wire (Red/White). A PITA but at least these are $0 checks.




ECM/BPM module issue would be down at the bottom of my list

edit: double check Fuse #14 (10A) in the engine management fusebox for the P0444 and P1251

 

thanks, i will get on it