CAN Communication Circuit Inspection

WARNING: This page is about a different car, the 2006 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.

CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the battery cable from the negative terminal.
3. Disconnect the harness connector for each unit on the CAN network and check terminals for deformation, disconnection, looseness or damage.
OK or NG
- OK : GO TO 2.
- NG : Repair terminal or connector as necessary.

CHECK HARNESS FOR SHORT CIRCUIT

With all module and control unit connectors disconnected, check continuity between data link connector terminals.

TERMINAL CONTINUITY CHART

Data link connector	Terminal		Continuity
M22	6	14	No

Fig 1: Identifying Continuity Between Data Link Connector Terminals

Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK : GO TO 3.
NG :
- Repair harness.
- Change harness if shielded lines are used for the harness.

CHECK HARNESS FOR SHORT CIRCUIT

Check continuity between data link connector terminals and ground.

TERMINAL CONTINUITY CHART

Data link connector	Terminal		Continuity
M22	6	Ground	No
M22	14	Ground	No

Fig 2: Identifying Continuity Between Data Link Connector Terminals And Ground

Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK : GO TO 4.
NG :
- Repair harness.
- Change harness if shielded lines are used for the harness.

ECM AND IPDM E/R INTERNAL CIRCUIT INSPECTION

Remove ECM and IPDM E/R from vehicle.

Check resistance between ECM terminals.

TERMINAL RESISTANCE CHART

Terminal		Resistance (Approx.)
94	86	108 - 132 Ω

Check resistance between IPDM E/R terminals.

TERMINAL RESISTANCE CHART

Terminal		Resistance (Approx.)
39	40	108 - 132 Ω

Fig 3: Identifying Resistance Between ECM Terminals

Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK : GO TO 5.
NG : Replace ECM and/or IPDM E/R.

CHECK SYMPTOM
1. Fill in described symptoms on the column "Symptom" in the check sheet.
2. Connect all connectors, and then make sure that the symptom is reproduced.
OK or NG
- OK : GO TO 6.
- NG : Refer to "EXAMPLE OF FILLING IN CHECK SHEET WHEN INITIAL CONDITIONS ARE NOT REPRODUCED ".
UNIT REPRODUCIBILITY INSPECTION
Perform the following procedure for each unit on the CAN network, and then perform reproducibility test.
1. Turn ignition switch OFF.
2. Disconnect the battery cable from the negative terminal.
3. Disconnect the unit connector.
4. Connect the battery cable to the negative terminal.
5. Make sure that the symptom filled in the "Symptom" of the check sheet is reproduced. (Do not confuse it with the symptom related to removed unit.)
6. Make sure that the same symptom is reproduced.
Inspection results
- Reproduced : Install removed unit, and then check the other unit.
- Not reproduced : Replace removed unit.