Bristol
Hi guys, new member here.
Recently bought a 2006 2.5si with 72000 miles for what I think was an absolute bargain price of £1300 - hood didn't go down (was the microswitch in the boot), an oil leak from the valve cover gasket (bmw things...) and the car won't communicate with the CAS when interrogated by ista. The first two issues were an easy fix however I'm stumped on the last one.
Ista is refusing to communicate with the CAS module - now as I understand it BMW only introduced the CAS module to the Z4 in 2006 - my car was made in 01/2006 so is a facelift however I can't seem to find the CAS module anywhere the forums suggest it might be (doesn't help that its a right hand drive as most posts are about LHD models). What adds further confusion is I'm also getting intermittent no comms with the DME and EPS modules which seem to only pop up after I've taken the car for an extended drive, and once I've cleared the codes through ista they don't come back (until I take the car out for a spin...)
The car starts on the button and drives fine
Current issues with the car include:
- Occasional engine light popping up; scanning through ista (haven't got myself a decent independent obd scanner yet) it says no comms with DME, EPS, CAS.
- The car seems down on power; I also own a supercharged mx5 with similar power figures so my butt dyno is telling me its not using the full potential of the engine - might be wrong on this.
- I'm getting the classic symptoms of the eccentric shaft sensor being dead (or a vacuum leak?) of very occasional idle drop to almost stalling then picking back up, as well as between 1500-2000 rpm theres a hesitation in accelerating and/or the car "bogging down" that suggests its running on the throttle body and not using the valvetronic system.
- The central locking will work however after 30secs or so will alarm - I think this is a dodgy bonnet (hood for you US fellas) security sensor which I have on order.
- Driver’s side window doesn't auto close when opening/closing the roof, however does operate when opening/shutting the doors.
My theories so far (bearing in mind I know how to work a spanner on an mx5 but these German electrical issue are all new to me) are:
- CAN bus issues; easy to check right? Check voltage and resistance over pin 6 & 14 on the obd port, but no BMW didn't use them with the E85. Fine, check the KBUS through the connection block? Mine doesn't have one... having spent 2 weekends contorting myself to get under the dash/passenger footwell to try and find the block I came across a post from a bloke who has a Z4M with what looks to be identical wiring to mine (albeit LHD). Being a mechanically minded person with little knowledge on electrical issues I'd love suggestions on this...
- Eccentric shaft sensor is f**ked? I suspect this is the case anyway which would explain the issues I'm getting wrt the bogging down and occasional EML, however could this cause issues with the KBUS?
- ISTA thinks the car has a CAS module when it doesn't and is getting confused; I'm tempted to ignore the non-comms and try to fix the rough idle with a new eccentric shaft sensor (already checked for vacuum leaks in the intake (havn't checked pcv system however its all refreshed with febi parts).
What's weird is none of the classic KBUS symptoms are there - the car works perfectly, radio, headlights, indicators etc. (maybe down on power, rough idle etc. but could be explained by sensors/vacuum leaks).
Would love any advise on CAS modules in early 2006 cars (did they have them?), KBUS diagnostics when I don't have a KBUS connection block, and experiences with eccentric shaft sensors failing. I've included the screenshots from ista on the faults I'm getting for context.
Cheers and apologies for the long post..!
Sam
Recently bought a 2006 2.5si with 72000 miles for what I think was an absolute bargain price of £1300 - hood didn't go down (was the microswitch in the boot), an oil leak from the valve cover gasket (bmw things...) and the car won't communicate with the CAS when interrogated by ista. The first two issues were an easy fix however I'm stumped on the last one.
Ista is refusing to communicate with the CAS module - now as I understand it BMW only introduced the CAS module to the Z4 in 2006 - my car was made in 01/2006 so is a facelift however I can't seem to find the CAS module anywhere the forums suggest it might be (doesn't help that its a right hand drive as most posts are about LHD models). What adds further confusion is I'm also getting intermittent no comms with the DME and EPS modules which seem to only pop up after I've taken the car for an extended drive, and once I've cleared the codes through ista they don't come back (until I take the car out for a spin...)
The car starts on the button and drives fine
Current issues with the car include:
- Occasional engine light popping up; scanning through ista (haven't got myself a decent independent obd scanner yet) it says no comms with DME, EPS, CAS.
- The car seems down on power; I also own a supercharged mx5 with similar power figures so my butt dyno is telling me its not using the full potential of the engine - might be wrong on this.
- I'm getting the classic symptoms of the eccentric shaft sensor being dead (or a vacuum leak?) of very occasional idle drop to almost stalling then picking back up, as well as between 1500-2000 rpm theres a hesitation in accelerating and/or the car "bogging down" that suggests its running on the throttle body and not using the valvetronic system.
- The central locking will work however after 30secs or so will alarm - I think this is a dodgy bonnet (hood for you US fellas) security sensor which I have on order.
- Driver’s side window doesn't auto close when opening/closing the roof, however does operate when opening/shutting the doors.
My theories so far (bearing in mind I know how to work a spanner on an mx5 but these German electrical issue are all new to me) are:
- CAN bus issues; easy to check right? Check voltage and resistance over pin 6 & 14 on the obd port, but no BMW didn't use them with the E85. Fine, check the KBUS through the connection block? Mine doesn't have one... having spent 2 weekends contorting myself to get under the dash/passenger footwell to try and find the block I came across a post from a bloke who has a Z4M with what looks to be identical wiring to mine (albeit LHD). Being a mechanically minded person with little knowledge on electrical issues I'd love suggestions on this...
- Eccentric shaft sensor is f**ked? I suspect this is the case anyway which would explain the issues I'm getting wrt the bogging down and occasional EML, however could this cause issues with the KBUS?
- ISTA thinks the car has a CAS module when it doesn't and is getting confused; I'm tempted to ignore the non-comms and try to fix the rough idle with a new eccentric shaft sensor (already checked for vacuum leaks in the intake (havn't checked pcv system however its all refreshed with febi parts).
What's weird is none of the classic KBUS symptoms are there - the car works perfectly, radio, headlights, indicators etc. (maybe down on power, rough idle etc. but could be explained by sensors/vacuum leaks).
Would love any advise on CAS modules in early 2006 cars (did they have them?), KBUS diagnostics when I don't have a KBUS connection block, and experiences with eccentric shaft sensors failing. I've included the screenshots from ista on the faults I'm getting for context.
Cheers and apologies for the long post..!
Sam
