4.
Read "DTC Status" parameter
A communication line exists between the Engine Control Module(ECM) and the Transaxle Control Module(TCM). The communication is through a Control Area Network(CAN). Without CAN communication, an independent pin and wiring is needed to receive a sensor information from a ECM. The more information to be communicated, the more wirings is required. In case of CAN communication type, all the information need to be communicated among control modules such as ECM and ABS control module use CAN lines.
The PCM determines CAN commuication error and sets DTC U0001 if communication with other control devices (e.g. ABS) via CAN is impossible or PCM detects that communication time via CAN exceeds threshold value.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Check CAN message transfer status | ● Open or short in CAN line ● Poor connection or damaged harness ● Faulty PCM |
Enable Conditions | ● Battery voltage >10V ● Delay time >0.5 sec. | |
Threshold Value | ● 20 wrong messages received by PCM | |
Diagnostic Time | ● - | |
Mil On Condition | ● 2 Driving Cycles |
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
Press F4(DTAL) to select DTC information from the DTCs menu
Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
Read "DTC Status" parameter
Is parameter displayed "History(Not Present) fault"?
History (Not Present) fault : DTC occurred but has been cleared.
Present fault : DTC is occurring at present time.
 | ▶ Fault is intermittent caused by poor contact in the sensor(s) and/or the PCM's connector was repaired and PCM memory was not cleared. Thoroughly check connectors for loose or poor connections, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure. |
 | ▶ Go to "W/Harness Inspection" procedure |
Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
| ▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure |
| ▶ Go to "CAN High line Inspection" procedure |
[ With ABS]
Ignition "OFF"
Disconnect PCM and ABS(or ESC or 4WD ECM) module connector
Measure resistance between terminals 7 of the PCM harness connectors and 11 of the ABS control module harness connector
Specification : Approx. 0Ω
Is resistance within the specification?
| ▶Go to "Check for short to ground in harness" procedure |
| ▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure. |
[ Without ABS]
Measure resistance between terminals 7 of the PCM harness connectors and 2 of the vertical resistor
Specification : Approx. 0Ω
Is resistance within the specification?
| ▶Go to "Check for short to ground in harness" procedure |
| ▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure. |
Measure resistance between terminals 7 of the PCM harness connectors and chassis ground
Specification : Infinite
Is resistance within the specification?
| ▶Go to next step as below |
| ▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure. |
Ignition "ON" & Engine "OFF"
Measure voltage between terminals 7 of the PCM harness connectors and chassis ground
Specification : Approx. 0V
Is voltage within the specification?
| ▶ Go to "CAN Low Line Inspection" procedure |
| ▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure. |
[ With ABS]
Ignition "OFF"
Disconnect PCM and ABS(or ESC or 4WD ECM) module connector
Measure resistance between terminals 6 of the PCM harness connectors and 10 of the ABS control module harness connector
Specification : Approx. 0Ω
Is resistance within the specification?
| ▶Go to "Check for short to ground in harness" procedure |
| ▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure. |
[ Without ABS]
Measure resistance between terminals 6 of the PCM harness connectors and 1 of the vertical resistor
Specification : Approx. 0Ω
Is resistance within the specification?
| ▶Go to "Check for short to ground in harness" procedure |
| ▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure. |
Measure resistance between terminals 6 of the PCM harness connectors and chassis ground
Specification : Infinite
Is resistance within the specification?
| ▶Go to next step as below |
| ▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure. |
Ignition "ON" & Engine "OFF"
Measure voltage between terminals 6 of the PCM harness connectors and chassis ground
Specification : Approx. 0V
Is voltage within the specification?
| ▶ Using a scan tool, check PCM software version and upgrade as necessary. If version is the newest one, go to "Verification of Vehicle Repair" procedure |
| ▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure. |
Ignition "OFF"
Measure resistance between High signal terminal and Low signal terminal of PCM connector(PCM side).
Specification : Approx. 110~130Ω
Is resistance within the specification?
| ▶ Check for poor connection between PCM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure |
| ▶ Check ECM for contamination, deterioration, or damage. Substitute with a known-good PCM and check for proper operation. If the problem is corrected, replace PCM and then go to "Verification of Vehicle Repair" procedure. |
After a repair, it is essential to verify that the fault has been corrected.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
Press F4(DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
Read "DTC Status" parameter
Is parameter displayed "History(Not Present) fault"?
| ▶ System performing to specification at this time. Clear the DTC |
| ▶ Go to the applicable troubleshooting procedure. |
