CAN-Bus Terminal Resistance, CHECKING

General Description

The Engine Control Module -J623- communicates with other CAN-Bus capable control modules.

The control modules are connected by two data bus wires which are twisted together (CAN_High and CAN_Low), and exchange information (messages). Missing information on the CAN-bus is recognized as a malfunction by the Engine Control Module -J623- and the other control modules connected to the CAN-bus.

Trouble-free operation of the CAN-Bus requires that it have a terminal resistance. This central terminal resistance is located in the Engine Control Module -J623-.

Special tools and workshop equipment required

Multimeter.
Wiring Diagram.

Test Requirements

Fuses OK.
Battery voltage OK.
Switch OFF all electrical and electronic accessories.
Vehicles with Auto. Transmission, ensure Selector Lever position is in "P".
Vehicles with Man. Transmission, ensure Shifter Lever position is in "N" with Parking Brake applied.
Coolant Temperature: ≥ 80° C.
Observe all safety precautions: SAFETY PRECAUTIONS .
View clean working conditions: CLEAN WORKING CONDITIONS .
For Hybrid vehicles refer to: HIGH VOLTAGE SYSTEM GENERAL WARNINGS .

Test Procedure

Step	Procedure	Result / Action to Take
1	PERFORM: Preliminary Check to verify the customers complaint. Refer to PRELIMINARY CHECK . -- Was Complaint verified?	-- YES: GO TO: Step 2 -- NO: GATHER more information from customer about the complaint.
2	IGNITION: OFF. DISCONNECT: Data Bus On Board Diagnostic Interface -J533- harness connector. The Engine Control Module -J623- must remain connected for the following step. For 2007 - 2009 MY, CHECK: Data Bus On Board Diagnostic Interface -J533- harness connector terminals 26 to 13 for resistance. For 2010 MY, CHECK: Data Bus On Board Diagnostic Interface -J533- harness connector terminals 6 to 16 for resistance. SPECIFIED VALUE: 60 - 72 Ω (@ approx. 20° C). -- Was Value obtained?	-- YES: CONDITION: May be intermittent. PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 4 -- NO: GO TO: Step 3
3	REMOVE: Engine Control Module - J623-. Refer to appropriate repair information. For 2007 - 2009 MY, CHECK: Data Bus On Board Diagnostic Interface -J533- harness connector terminal 26 to the Engine Control Module - J623- harness connector T94 / 67 for resistance. For 2010 MY, CHECK: Data Bus On Board Diagnostic Interface -J533- harness connector terminal 6 to the Engine Control Module - J623- harness connector T94 / 67 for resistance. For 2007 - 2009 MY, CHECK: Data Bus On Board Diagnostic Interface -J533- harness connector terminal 13 to the Engine Control Module - J623- harness connector T94 / 68 for resistance. For 2010 MY, CHECK: Data Bus On Board Diagnostic Interface -J533- harness connector terminal 16 to the Engine Control Module - J623- harness connector T94 / 68 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	-- YES: REPLACE: Engine Control Module -J623-. Refer to appropriate repair information. GO TO: Step 4 -- NO: PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 4
4	Final Procedure Perform a road test to verify repair. -- Does the original DTC return?	-- YES: CHECK: Data Bus On Board Diagnostic Interface -J533- harness connector for any damaged, pushed-out pins. REPAIR: As necessary. Clear the DTCs. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY . Repair is complete. Generate Readiness Code. Refer to READINESS CODE . Return vehicle to Customer. If all electrical connections are OK: REPLACE: Data Bus On Board Diagnostic Interface -J533-. Refer to appropriate repair information. Repair is complete. Generate Readiness Code. Refer to READINESS CODE . Return vehicle to Customer. -- NO: Perform the diagnostic procedure for any DTC's. If no DTC's return, the repair is complete. Return vehicle to customer.