ON-BOARD DIAGNOSTIC FUNCTION [CAN (CONTROLLER AREA NETWORK)]

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On-Board Diagnostic Function


Malfunction detection function

•  The failure detection function in each CAN system-related module detects malfunctions in input/output signals.
•  This function outputs the DTC for the detected malfunction to the DLC-2, and also sends the detected result to the memory function and fail-safe function.


Fail-safe function

•  When the failure detection function determines that there is a malfunction, the fail-safe function illuminates a warning light to inform the driver of the malfunction.


Memory function

•  The memory function stores the DTC for the malfunction of input/output signals for related parts, as determined by the failure detection function.


Self-malfunction diagnostic function

•  The self-malfunction diagnostic function determines that there is a malfunction, and outputs a signal, as a DTC, to the DLC-2. The DTC can be read out using the Mazda Modular Diagnostic System (M-MDS).

HS-CAN

DTC output module

(M-MDS display)

DTC

Malfunction location
PCM (MZR 1.3, MZR 1.5)
(PCM)
U0073:00
CAN system communication error
U0121:00
•  Communication error to ABS HU/CM (with ABS)
•  Communication error to DSC HU/CM (with DSC)
U0140:00
Communication error to BCM
U0151:00
Communication error to SAS control module
U0155:00
Communication error to instrument cluster
PCM (MZ-CD 1.6)
(PCM)
U0001:00
CAN system communication error
U0073:00
CAN system communication error
U0121:00
•  Communication error to ABS HU/CM (with ABS)
•  Communication error to DSC HU/CM (with DSC)
U0122:86
U0122:87
U0155:00
Communication error to instrument cluster
U0167:00
U0121:00
•  Communication error to keyless control module (vehicles with advanced keyless and start system)
•  Communication error to instrument cluster (vehicles with keyless entry system)
ABS HU/CM*1
(ABS)
U0001:88
CAN system communication error
U0100:00
Communication error to PCM
U0155:00
Communication error to instrument cluster
U2101:00
Signal error from instrument cluster
DSC HU/CM*2
(ABS)
U0001:88
CAN system communication error
U0100:00
Communication error to PCM
U0126:00
Communication error to EPS control module
U0155:00
Communication error to instrument cluster
U0401:68
Signal error from PCM
U2101:00
Signal error from instrument cluster
SAS control module
(RCM)
U0001:88
CAN system communication error
U0155:00
Communication error to instrument cluster
BCM
(BCM/GEM)
U0001:88
CAN system communication error
U0100:00
Communication error to PCM
U0101:00
Communication error to TCM
U0121:00
•  Communication error to ABS HU/CM (with ABS)
•  Communication error to DSC HU/CM (with DSC)
U0415:68
•  Signal error from ABS HU/CM (with ABS)
•  Signal error from DSC HU/CM (with DSC)
TCM*3
(TCM)
U0073:00
CAN system communication error
U0100:00
Communication error to PCM
U0121:00
•  Communication error to ABS HU/CM (with ABS)
•  Communication error to DSC HU/CM (with DSC)
Keyless control module*4
(RKE)
U0001:88
CAN system communication error
U0028:87
Communication error to BCM
U0100:00
Communication error to PCM
U0401:68
Signal error from PCM
EPS control module
(EPS)
U0001:88
CAN system communication error
U0100:00
Communication error to PCM
U0401:00
Signal error from PCM
Theft-deterrent control module*5
(VSM)
U0001:88
CAN system communication error
U0100:00
Communication error to PCM
U0155:00
Communication error to instrument cluster
Instrument cluster
(IC)
U0001:88
CAN system communication error
U0100:00
Communication error to PCM
U0101:00
Communication error to TCM
U0121:00
•  Communication error to ABS HU/CM (with ABS)
•  Communication error to DSC HU/CM (with DSC)
U0131:00
Communication error to EPS control module
U0140:00
Communication error to BCM
U0151:00
Communication error to SAS control module
U0214:00
Communication error to keyless control module
U0401:68
Signal error from PCM
U0401:92
Signal error from PCM
U0402:68
Signal error from TCM
U0402:92
Signal error from TCM
U0415:92
•  Signal error from ABS HU/CM (with ABS)
•  Signal error from DSC HU/CM (with DSC)
U0420:92
Signal error from EPS control module
U0452:68
Signal error from SAS control module
U0452:92
Signal error from SAS control module
U0515:68
Signal error from keyless control module
U0515:92
Signal error from keyless control module
U2005:86
Signal error from PCM

*1  :With ABS
*2  :With DSC
*3  :CVT
*4  :With advanced keyless entry and start system
*5  :With theft-deterrent system


Narrowing down malfunction locations

•  When the CAN system is thought to be malfunctioning based on the repair order form and the malfunctioning symptom, perform the CAN system on-board diagnosis.
•  DTCs are output due to a control module or sensor malfunction, or incorrect power supply. Verify the output DTCs and first inspect the DTCs not shown in the DTC table.
•  The open circuit location in the CAN system can be determined by verifying the DTCs detected in each module and by the module which has failed.
•  It is possible for signal error DTCs to be output in addition to communication error DTCs if there is an open circuit. Determine the open circuit location if the communication error and signal error DTCs are output simultaneously.
•  For DTC details, refer to the “Self-malfunction diagnostic function”. (See Self-malfunction diagnostic function.)

Troubleshooting procedure

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Example (L.H.D.): DSC HU/CM-related wiring harness open circuit (if DTC is output)

1.  Verify the CAN system-related module DTCs and the failed module using the Mazda Modular Diagnostic System (M-MDS).

Module

Displayed DTC

Probable malfunction location
PCM (PCM)
U0121:00
Communication error to DSC HU/CM
BCM (BCM/GEM)
U0121:00
Communication error to DSC HU/CM
IC (Instrument cluster)
U0121:00
Communication error to DSC HU/CM

Module

Fail
ABS (DSC HU/CM)
×

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2.  Despite normal communication between the PCM and instrument cluster, a communication error DTC is displayed for the signal between the DSC HU/CM and PCM / BCM / instrument cluster. In addition, the wiring harness between the DSC HU/CM and branch A is considered to be malfunctioning because “Fail” is displayed for the DSC HU/CM.


Example (R.H.D.): DSC HU/CM-related wiring harness open circuit (if DTC is output)

1.  Verify the CAN system-related module DTCs and the failed module using the Mazda Modular Diagnostic System (M-MDS).

Module

Displayed DTC

Probable malfunction location
PCM (PCM)
U0121:00
Communication error to DSC HU/CM
BCM (BCM/GEM)
U0121:00
Communication error to DSC HU/CM
TCM (TCM)
U0121:00
Communication error to DSC HU/CM
IC (Instrument cluster)
U0121:00
Communication error to DSC HU/CM

Module

Fail
ABS (DSC HU/CM)
×

am2zzn00001509

2.  Despite normal communication between the PCM and instrument cluster, a communication error DTC is displayed for the signal between the DSC HU/CM and PCM / BCM / TCM / instrument cluster. In addition, the wiring harness between the DSC HU/CM and branch A is considered to be malfunctioning because “Fail” is displayed for the DSC HU/CM.