P1764

DTC P1764 CAN MI-COM OR CIRCUIT MALFUNCTION





COMPONENT LOCATION

GENERAL DESCRIPTION
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 TCM use CAN lines.

DTC DESCRIPTION
After clearing the DTC, check the malfunction of TCM and 4WD ECM, if the DTC sets again. This code may set if there is no signal to 4WD ECK





DTC DETECTING CONDITION





SCHEMATIC DIAGRAM

WAVEFORM INSPECTION
1. IG KEY ON, ENG ON
2. TCM or 4WD EGM connector: Connect.





3. Monitor signal waveform between terminal 3 & 4 of TCM harness connector and chassis ground.

MONITOR SCANTOOL DATA
When the DTCs related to CAN communication set, use the sensor data (TCM side) to check for the ECM & TCM's communication condition. Check the data such as the engine RPM and the throttle position sensor at idle in order to inspect the signal between ECM and TCM.

TERMINAL & CONNECTOR INSPECTION
1. Many malfunctions in the electrical system may be caused from poor harness and terminals. These faults can be caused by interference from other electrical systems and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
YES Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO Go to the next procedure.

COMPONENT INSPECTION
1. TCM component inspection
1) IG KEY OFF, ENG OFF





2) Measure resistance between the terminal 3 and 4 with the specification below.
Specification: Without TCS, 4WD system
X-ECM connector and TCM connector: Connect - > 600 ± 1
X-ECM connector: Disconnect and TCM connector: Connect - > 1200 ± 20
X-ECM connector: Connect and TCM connector: Disconnect - > 1200 ± 20
Specification: With TCS, 4WD system
X-ECM connector and TCM connector: Connect - > 1200 ± 20
Is resistance display near the specified value?
YES Check if ECM-TCM communication line is short to ground.
NO Check if ECM-TCM communication line is open.
2. ECM waveform inspection
1) IG KEY OFF, ENG OFF
2) TCM connector: Disconnect.
3) Connect the terminal 3 and 4 of TCM connector to a scan tool.





4) IG KEY ON
Is CAN Signal display near the specified value?
YES Inspect TCM waveform.
NO ECM communication signal malfunction - replace ECM.
After checking 4WD ECM circuit, if any malfunction is detected, replace 4WD ECM.
3. TCM waveform inspection
1) IG KEY OFF, ENG OFF
2) ECM connector: Disconnect.
3) Connect the terminal 9 and 10 of ECM connector to a scan tool.
4) IG KEY ON
Is CAN Signal display near the specified value?
YES TCM is in a normal condition.
NO TCM communication signal malfunction - replace TCM.
After checking 4WD ECM circuit, if any malfunction is detected, replace 4WD ECM.

SIGNAL CIRCUIT INSPECTION
1. ECM-TCM communication line open inspection
1) IG KEY OFF, ENG OFF
2) ECM connector and TCM connector: Disconnect.





3) Measure resistance between terminals 10 of the ECM harness connector and 3 of the TCM harness connector. Measure resistance between terminals 9 of the ECM harness connector and 4 of the TCM harness connector.
Specification: Approximately 0 ohms
Is resistance display near the specified value?
YES Check if ECM-TCM communication line is short.
NO Repair open circuit of CAN Low comm. Line.

GROUND CIRCUIT INSPECTION
1. ECM-TCM communication line short to ground inspection
1) IG KEY OFF, ENG OFF
2) TCM connector, ECM connector, 4WD ECM connector and TCS (or ESP) connector: Disconnect.
3) Measure resistance between terminal 4 of TCM harness connector and chassis ground.





4) Measure resistance between terminal 3 of TCM harness connector and chassis ground.
Specification: Approximately 0 ohms
Is resistance display near the specified value?
YES Go to the "Component inspection".
NO Repair ground to short circuit of CAN Low comm. Line.
If problem is solved, go to the "Verification of Vehicle Repair".