2006 H6 Liberty 5500rpm limiter

[RickiBobby]

Hi Race fans, strap in for abit of a long story,
About 6 months ago I purchased a 2006 Liberty manual 3.0L from the auctions as a repairable write off to use as a Khanacross/Rallysprint car, it had a fairly light hit in the front that hadn't set the airbags off and didn't come with the front bar, passengers side guard and headlight. I purchased these parts and took it for a cheeky lap around the block and it all seemed to drive fine.
Fast forward a few months and Ive stripped the interior out and fitted a race seat which triggered the air bag light on the dash and a few weeks later took it for a spin and putting it back on the trailer noticed it hits a rev limiter at 5500rpm but doesn't bring up the CEL, a mate who put a H6 into his old impressa had warned me that they have a very complicated CANBUS system that for safety could trigger this limiter. No worries I thought and put the factory seats back in and the airbag light on the dash went away but the 5500rpm limiter is still happening. The next thought process was old stale fuel triggering a knock sensor so I removed the old fuel and replaced with 98, no different, maybe a dirty MAF which I removed and cleaned but limiter is still there. Whilst doing these 2 things I did crank the car with the MAF disconnected with then triggered the CEL and flashing cruise control light, I hooked up a very basic OBD11 scanner which revealed 2 fault codes, MAF and an Inlet air temp, both of which went away when the MAF was reconnected and cleared with the scanner.
The other things I have noticed that arent working and will attempt to rectify over the weekend are the drivers side headlight isn't working, the fog lights aren't installed in the front bar, and the windscreen washer bottle has been removed, looking at what I think is the washer bottle and passengers side foglight connectors they appear to have 12 volts on them constantly when the car is running, does anyone know if this is correct and they are a switched negative wiring system??
Also from what I've read online you need a different scanner to talk to the CANBUS system as OBD11 will only talk to the engine ECU, so if I do manage to rectify whatever is triggering the 5500rpm limiter will I then need to get a mechanic with one of these scanners to clear it or would it clear itself like the airbag light on the dash did when the seats were plugged back in??
I've also read a similar case where a faulty CPS had triggered this limiter so I will remove the CPS on mine and see what it reads with a meter
The only other thing that has been changed was the front discs and rotors were replaced with smaller ones off a 2 litre Liberty as we need to run 15" rims for Rally tires but I wouldn't have thought the computer would be smart enough to know this had been done??
Ok peoples TIA if anyone has any ideas or has seen this sort of issue before and can offer some advice its much appreciated

[nvmylh]

Have you got a bluetooth OBD2 reader handy? Try downloading BTSSM on your phone? That seems to find every fault code fairly easily from what I've seen (and clears them).

It'll come in handy if you want to keep and eye on temps when rallying too

[RickiBobby]

No Bluetooth OBD reader just an old cheap plug in one which I used to clear the MAF and IAT codes it threw when I cranked it with the MAF unplugged
I was under the impression you needed a different scan tool and laptop to read any of the CANBUS faults as they don't go through the engine ECU??

[bigBADbenny]

You can try Btssm, freessm or Romraider: with a $15 eBay vagcom, clear blue case type with usb A male plug.

For Btssm on an android *phone* also buy the female usb A OTG adapter to suit your phone.

You can also display codes on the odometer.

Your stock limiter rpm might probably be listed in the FSM workshop manual?

You’ll need a Tactrix and Romraider to flash an updated tune, including your preferred rpm limit.

You want virtual gauges regardless, plus parameter alarms so Btssm is a must.

Generic obdii using an elm327 or iOS bt plug with the appropriate app is the the absolute minimum option, if nothing else, and it’s a great start.

You can and should defeat the seat airbag cel using an airbag resistor, doing so will fix the cel and allow the other airbags to remain active: for track use only.

A multimeter can be used for the most basic canbus diagnostics, the specific voltages, plug locations and pinouts are again in the FSM. Iirc the twisted pair wires are referenced to ecu ground, red goes positive, blue goes to negative at around 3.5V, eg if you find a comms issue, you may then use plug to plug continuity/voltage drop tests.

On 2.5i, a busted brake bulb is a classic no cel limp mode trigger.

Additionally there’s various SSM ecu resets available, some can be accessed using freessm, or dealership level SSM scan tool, including BCM, SAS, VDC etc, generally anything Canbus related.

More detail in the red FSM link in my signature..