NEED help to diagnose the issue
Dear all diagnostic tecnicians,
I'm writing this post to ask if anyone can help me to rectify this issue as below.
Vehicle: MY12 Mazda CX5 Diesel 2.2L 4WD Auto
Country: Australia
Symptom sequence:
>> Need to drive the vehicle about 30 min" and stop & leave the vehicle about 5 min' with the engine running and the engine will jerk, the acceleration will have no responce and eventually, the engine will stall as take off
>>the engine will start straight way with one go after stalling and there is no DTC at the time of event
>>the issue will not happen if drive without stopping
>>one day the ABS,DSC(Dynamic Stability Control) TPMS warning lights came on and all TDCs as below triggered
ECU | DTC CODE | DTC Description | STATUS |
ABS | U0452 | Abnormal message from SAS control module | Current |
Airbag | C0063 | Yaw rate sensor in SAS control module | Current |
TPMS | U0452 | Abnormal message from SAS control module | Current |
EPS | U0415 | Signal error from DSC HU/CM | Current |
Forward sensing camera | U0415 | Invalid data received from ABS control module | Current |
C1001 | Vision system camera | Current |
>>if drive with the air bag control module disconnected, the issue is not occuring any more and confirm this a couple of times because I have came across the faulty YAW rate sensor signal can tirbute power limits as TCS or DCS will request power/torque limit to ECU if there is excessive YAW rate signal present (the YAW rate sensor is in the air bag control module)
>>found also,the engien rpm become unstable(it looks like minor misfire) before the symptom (stalling) occurs but the engine runs perfect with the air bag module disconnected
>>replaced & coded the air bag control module and calibrated the YAW rate sensor from Mazda dealer but the issue is still present
>>suspect the ABS module is causing the issue but can't see any torque limit request from ABS module at the time of event
>>I don't think it's engine or fuel related issue because it will start straight way after stalling and the fuel data(measured & command) are corresponding at the time of event and also there is no issue if drive with the air bag control module disconnected
>>the YAW rate sensor signal at stand still looks too excessive to me
Parts replaced: Air bag control module, MAP/Boost pressure sensor, fule filter
Thank you in advance and God bless you all,
Regards,
Freddy …
Thank you Danh, may be but not sure and I need evidence to change any parts from now on. Freddy
Does the Airbag Control Module have good powers and grounds At All Times (confirmed with lengthy oscilloscope capture)?
Hi Dmitriy, I didn't confirm the powers & grounds with oscilloscope but did confirm it has good powers & grounds with voltage drop at the time of event. Freddt
Sounds like you have a common problem causing all of the issues. Some things just won't pick up on a scan tool or set a code. Like low fuel pressure or a failed pump. I'm thinking you have a power/ground issue or a bad battery not up to full charge. Maybe a bad cell dragging it down. Could just be a bad connection at the battery or fuse box. These modern cars computers are very sensitive to…
Is it possible to monitor all relative dat, load , tps, all relevant commands to control idle and throttle, find out first what is being commanded to shut off then read service data on fault setting criteria and action taken.
Thank you for your input Matthew, I did have a look all data at the time of event like you said but can't see any abnormal data. The sanp on tool(Modis edge) doen't give much information like factory scan tool and wish to have flight record feature in it. Freddy
Hi Jesse, thank you for your input. will keep in mind that but it's not fuel related issue as it starting straight way after stalling. The vehicle has a denso fuel system which has no low pressure fuel pump in the tank but using a suction pump in the high pressure fuel pump. If this vehicle has fuel starving issue, it won't start straight way after stalling and further more no issue at…
I'm not saying it is fuel related. I'm saying that there is a common issue somewhere in the system linking everything together. One bad sensor or module/computer can cause other issues not related. Unplugging one at a time, if possible, is a good test. I was thinking about you saying that there was no throttle after sitting running for 5 minutes while in the store. I'm wondering if a weak…
Thank you Jesse for your input, Yes, I agreed with you. Something which is not related to engine is contributing the issue to cause engine performance issue and I think the ABS module is possible the cause of the problem but can't drive with ABS module disconnected as it will lose power steering assisst. The vehicle starts straight way with one go/no delay/no weak cranking after stalling, so I…
Hi Jesse, thank you for your input. I will keep in mind that but it's not fuel related issue as it starting straight way after stalling. The vehicle has a denso fuel system which has no low pressure fuel pump in the tank but using a suction pump in the high pressure fuel pump. If this vehicle has fuel starving issue, it won't start straight way after stalling and further more no issue at…
Hi Kyle, Thank you for your reply. Please see the table in the post. Freddy
Hello Freddy, Judging from the multiple U codes and problem will not occur with the airbag module disconnected, I suspect the com lines going to the airbag module are pinched or damaged somehow. Check for any recent repair history or aftermarket devices added to the vehicle. The system strategy of many manufacturers is to disable engine and transmission components during a collision event…
Hi Glenn, Thank you for your reply. The yaw rate sensor related issue is not occuring any more after replacing airbag control module and the stalling issue is not occuiring with auto idle stop function activated. The front sensing camera or sensos not damaged and couldn't find any smash repair evidence. The issue is not occuring any more after driving 400kms and decided to realease the…
Hi Freddy, Anything new with the Mazda? did you solve the problem yet?
Hi Danh, May be becsue the issue is not occuring any more after changing the air bag control module and ABS module. It's hard call and don't like fix like this. Regards, Freddy
The issue is not occuring after driving about 400kms with new airbag control module & ABS control module replaced but not sure it fixed the issue. Also the issue is not occuring if the auto idle stop activated(it is default) Regards, Freddy
Hi Freddy, I understand how you feel. I think it might help if you look up a subject called Air Bag Systems and Vehicle Kinematics. In modern vehicle, “systems” are not stand-alone operations. The modern safety systems like air bags, ABS, steering along with the engine and transmission functions all communicate on CAN bus systems. If one has an issue the others are alerted and often react to…