Hello everyone
well back in New Zealand for a week from the United Kingdom
And the nightmare is still ongoing
Still have no communication with engine control module
On the 2003 str
Please note electrical issues are not my strong point
but I will keep on with it as then I can say at least I fixed it myself
So please I really need help
I know it is not the ecm as two can't be faulty
Both were Professionally programmed
fault codes I have are all related to ecm or can bus
but on testing can bus its reading 60.5 ohm battery disconnected
Power at diagnostic plug 16
Fault codes
U1900 can bus communication
U2523 can message time out to ecm this is from
Transmission / instrument cluster/ abs
I did have a pats code 15 issue with transponder key
But thats gone now

ok this is where I struggle
I have no power at fuse 18 engine compartment Ignition on
all other fues have power
On the post,s I have read some say cheek pins 1 & 3 on relay #4 engine compartment
one pin at relay 4 had power with ignition off
Two pins at relay 4 had power with ignition on
I purchased 14 new relay,s from sng Barratt before I came back to new Zealand
still made no difference
I have removed and Cleaned the earth wires
I have tested on ecm connector plug pin 134 gu
That has 12 .6 volts
I am now being to thick ecm is not getting the correct amount of power to wake it up
I am hoping some kind person on the forum will take the time to tell me what pins on ecm connector plug i need to test
and also how to test for switched power
As I'm beginning to feel like a headless chicken

I have just purchased a oscilloscope but that won't arrive for about 4 days

Any help would be greatly appreciated
Thanking you
Darrol

 

At least you have working CAN "terminating" resistors (roughly 60 ohms is good).

An ordinary OBD tool should be happy to talk to the PCM (aka ECM) over ISO9141-2 and may well not find the PCM over CAN.

So if such as an elm327 won't talk to the PCM ... er, could be any of quite a few problems, from bent pin in DLC (OBD connector) to wiring (chafed?) to something making the PCM truly unhappy e.g. the PCM isn't powered properly. Or several other things - sorry, I can't think of a full list.

For ISO 9141, our cars only use the K line (DLC pin7) and inevitably ground (pins 4 & 5), plus such as elm327 needs power (pin 16 for battery+).

Tools such as IDS/SDD will use CAN for the PCM but may start via ISO 9141.

If examining CAN, it's differential i.e. devices take the difference between the 2 CAN lines (it eliminates most electrical noise). When inactive the lines park at specified voltage levels.

BTW even an elm327 is able to send/receive CAN packets so can be persuaded to talk direct to PCM but most diagnostic software isn't set up to do it with our cars as the software will just find & use ISO 9141.

 

> So if such as an elm327 won't talk to the PCM ... er, could be any of quite a few problems, from bent pin in DLC (OBD connector) to wiring (chafed?)
Yes, maybe along those lines of thought: A pinched wire or a bad connection between one of those wires and their terminals (=pins) or surface-corrosion of one of those pins to the effect that there is no contact....
Is power getting thru to any of the relevant components?

PS: I have just been inspired by a brand new question on the X308 forum: Did you check all your ground connections?

 

The ground connection problems come from the Aluminum construction of those cars. Plus all that brings to the table with ground dissimilar metals. The S-Type is steel so that is not an issue.
.
.
.

 

PS: I have just been inspired by a brand new question on the X308 forum: Did you check all your ground connections?

The ground connection problems come from the Aluminum construction of those cars. Plus all that brings to the table with ground dissimilar metals. The S-Type is steel so that is not an issue.

The X308 is steel bodied, the X350 is aluminium ?

 

hi thanks Yes have checked all grounds
But the x202 s type is a steel body

 

Hi sorry for the late response
The elm 327 arived today
That won't even Communicate with car

 

Hi Peter long time no talk
I have had the complete dashbord out and tested every single wire oh boy what a job
end every thing was fine
have even put a brand new Diagnostic plug on from sng Barratt which i brought over from uk
I have purchased a brand new ignition switch which I hope arrives on Monday
because I keep getting fault code
B1352 key in circuit failure
So hopefully that might help
Cheers
Darrol

 

On the DLC (OBD socket) a typical elm327 (there are lots of clones, some better than others) needs battery+ (pin 16), one or both of the grounds (pins 4&5), and then:
7 ISO 9141 K-line
2&10 SCP
6&14 CAN

Your kind of PCM should talk via pin7. Maybe a loose/bent pin? Or, possibly try different OBD software for an elm327.

Another way is to use a "terminal" program. On Windows I guess it's hyperterminal or the like, on Android there are USB and BT (bluetooth) terminal programs (depends whether you have USB or BT elm327, I guess BT). You have to be quite keen to try any of them - let me know which OS (Android?) you've got if you want to try this but so far it looks like the wiring for the K-line is suspect.

 

Hello thank you foryou reply
I did some quick testing with multimeter and brakeout box
Pins 4 Ground pin 5 singnal ground both have Continuity
pin 16 has 12 .8 volts with pins 4&5
Pin 7 iso 941 k line .has 17.65 k ohms with ignition on and
20.8 k ohms with battery disconnected
Pins 2 & 10 have 121.8 ohms battery disconnected
I hope I'm testing correctly
Pins 6 & 14 canbus.62 ohms battery disconnected disconnected

As for the elm327 yes its a blue tooth one for Android
On a Samsung galaxy note 20
I do have a old note 9 as well
Still waiting for oscilloscope to arrive
Thanking you
Darrol

 

SCP & CAN are OK so far but your tool basically can't talk (with standard software) to much if anything on them.

K-line sounds like doesn't actually get to/from your PCM.

(That or your OBD tool is faulty.)

 

Thanks
I have 3 elm327 now yet none work on this car but do on other vehicles

Still trying to figure out why fuse 18 in engine compartment has no power
relay # 4 has power and been tested
I love the car and put a lot of blood sweat and tears in it
But now thinking about throwing in the towel
And sending it to a friends car crusher and calling it a day

 

Testing an OBD tool on another car (when it's the ISO K-line which is in doubt) would be great if that other car uses the K-line. Modern cars use CAN, though.

(Yes, your STR does use CAN but not for a simple OBD tool to talk to the PCM.)

 

The impedance he measured looks about right.

To the OP before crushing the car, wait for your scope to arrive and see what you have on the K line. Probably nothing with ignition off, and a good waveform with the ignition on.

Note that the L line might be used as a wake up signal.

 

L-line isn't used and isn't connected.

If there is a problem with the K-line it could be due to any of the other modules on it - see the Electrical Guide fig 20

 

Hi thanks
Unfortunately I don't know how to read or understand electrical diagrams
thats my biggest downfall
Give me a engine or transmission to rebuild no problem thats what I'm quifiled in
Did some mucking around today with the car
I jumped relay #4 throttle body pins 3 &5 got power to fuse 18 so at least I know that part of the wiring is ok
I know relay is fine as i took one out of the wifes car and put my one in and her car started straight away
I also have power at engine control module connector plug pin 134 which i think is for throttle body relay
So now just need to figure out what other pins to test on ecm connector plug

Hopefully the oscilloscope and new ignition switch arive tomorrow
As I keep getting key in Ignition Circuit failure so not sure if that could cause issues

Thanks for
Darrol