Steering Control System (Coupe): Diagnosis Nissan Altima L33

Diagnosis Procedure

Regarding Wiring Diagram information, refer to " WIRING DIAGRAM ".

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1. CHECK POWER SUPPLY Turn the ignition switch OFF. Disconnect power steering control unit harness connector. Check voltage between power steering control unit harness connector M59 terminal 3 and ground. Power steering control unit Voltage (Approx.) Connector Terminal M59 3 - Ground 0 V Turn the ignition switch ON. CAUTION: Never start the engine. Check voltage between power steering control unit harness connector M59 terminal 3 and ground. Power steering control unit Voltage (Approx.) Connector Terminal M59 3 - Ground Battery voltage Is the inspection result normal? YES: GO TO 2. NO: Check the following. If any items are damaged, repair or replace damaged parts. 10A fuses (#3) open Harness for short or open between ignition switch and power steering control unit harness connector No. 3 terminal. Ignition switch.
2. CHECK GROUND CIRCUIT Turn the ignition switch OFF. Check continuity between power steering control unit harness connector M59 terminal 6 and ground. Power steering control unit Continuity Connector Terminal M59 6 - Ground YES Is the inspection result normal? YES: GO TO 3. NO: Repair open circuit or short to power in harness or connectors.
3. CHECK TERMINALS AND HARNESS CONNECTORS Check power steering control unit pin terminals for damage or loose connection with harness connector. Is the inspection result normal? YES: Inspection End NO: Repair or replace damaged parts.

Regarding Wiring Diagram information, refer to " WIRING DIAGRAM ".

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1. CHECK POWER STEERING SOLENOID VALVE SIGNAL Start engine. Check voltage between power steering control unit harness connector M59 terminal 1 and ground. Power steering control unit Value (Approx.) Connector Terminal Condition M59 1 - Ground Vehicle speed: 0 km/h (0 MPH) (Engine is running) 4.4 - 6.6 V Vehicle speed: 100 km/h (62 MPH) 2.5 - 3.7 V Is the inspection result normal? YES: GO TO 2. NO: GO TO 4 .
2. CHECK HARNESS BETWEEN POWER STEERING SOLENOID VALVE AND POWER STEERING CONTROL UNIT Turn the ignition switch OFF. Disconnect power steering solenoid valve harness connector. Disconnect power steering control unit harness connector. Check the continuity between power steering solenoid valve harness connector E14 (A) terminal 1 and 2 and the power steering control unit harness connector M59 (B) terminal 1 and 5. Power steering solenoid valve Power steering control unit Continuity Connector Terminal Connector Terminal E14 (A) 1 M59 (B) 1 YES 2 5 Also check harness for short to ground and short to power. Is the inspection result normal? YES: GO TO 3. NO: Repair or replace damaged parts.
3. CHECK POWER STEERING SOLENOID VALVE Check resistance between power steering solenoid valve terminals. Power steering solenoid valve Resistance (Approx.) Terminal 1 - 2 5 ohms Check power steering solenoid valve by listening for its operation sound while applying battery voltage to power steering solenoid valve terminal 1 (positive) and battery ground to terminal 2 (negative). Is the inspection result normal? YES: GO TO 4. NO: Replace power steering solenoid valve. Refer to " «EXPLODED VIEW»(ref-592021-S25095276052014010800000) ".
4. CHECK TERMINALS AND HARNESS CONNECTORS Check power steering control unit pin terminals for damage or loose connection with harness connector. Check power steering solenoid valve pin terminals for damage or loose connection with harness connector. Is the inspection result normal? YES: Inspection End NO: Repair or replace damaged parts.

Regarding Wiring Diagram information, refer to " WIRING DIAGRAM ".

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1. PERFORM ECM SELF-DIAGNOSIS With CONSULT Perform ECM self-diagnosis. Is any error system detected? YES: Check the error system. NO: GO TO 2.
2. CHECK HARNESS BETWEEN ECM AND POWER STEERING CONTROL UNIT Turn the ignition switch OFF. Disconnect ECM harness connector E10 (QR25DE for USA and Canada), E31 (QR25DE for California). Disconnect power steering control unit harness connector. Check continuity between ECM harness connector E10 (QR25DE for USA and Canada), E31 (QR25DE for California) or (A) terminal 94 and power steering control unit harness connector M59 (B) terminal 10. ECM Power steering control unit Continuity Connector Terminal Connector Terminal E10 (QR25DE for USA and Canada) (A) 94 M59 (B) 10 YES E31 (QR25DE for California) (A) Also check harness for short to ground and short to power. Is the inspection result normal? YES: GO TO 3. NO: Repair or replace damaged parts.
3. CHECK ENGINE SPEED SIGNAL (ECM SIDE) Turn the ignition switch OFF. Connect ECM harness connector. Check signal between ECM harness connector E10 (QR25DE for USA and Canada), E31 (QR25DE for California) terminal 94 and ground with oscilloscope. ECM Value (Approx.) Connector Terminal Condition E10 (QR25DE for USA and Canada) E31 (QR25DE for California) 94 - Ground Engine speed: At idle (Warm-up condition) Engine speed: Approx. 2, 000 RPM (Warm-up condition) Also check harness for short to ground and short to power. Is the inspection result normal? YES: GO TO 4. NO: Replace ECM. Refer to " «COMPONENT PARTS LOCATION»(ref-592025-S21896585532014010800000) " (QR25DE for California), " «COMPONENT PARTS LOCATION»(ref-592026-S10336548642014010800000) " (QR25DE for USA and Canada).
4. CHECK ENGINE SPEED SIGNAL (POWER STEERING CONTROL UNIT SIDE) Turn the ignition switch OFF. Connect power steering control unit harness connector. Check signal between power steering control unit harness connector M59 terminal 10 and ground with oscilloscope. Power steering control unit Value (Approx.) Connector Terminal Condition M59 10 - Ground Engine speed: At idle (Warm-up condition) Engine speed: Approx. 2, 000 RPM (Warm-up condition) Also check harness for short to ground and short to power. Is the inspection result normal? YES: GO TO 5. NO: Replace power steering control unit. Refer to " «REMOVAL AND INSTALLATION»(ref-592052-S27886428512014010800000) ".
5. CHECK TERMINALS AND HARNESS CONNECTORS Check power steering control unit pin terminals for damage or loose connection with harness connector. Check ECM pin terminals for damage or loose connection with harness connector. Is the inspection result normal? YES: Inspection End NO: Repair or replace damaged parts.

Regarding Wiring Diagram information, refer to " WIRING DIAGRAM ".

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1. PERFORM COMBINATION METER SELF-DIAGNOSIS Perform combination meter self-diagnosis. Is any error system detected? YES: Check the error system. NO: GO TO 2.
2. CHECK HARNESS BETWEEN COMBINATION METER AND POWER STEERING CONTROL UNIT Turn the ignition switch OFF. Disconnect combination meter harness connector. Disconnect power steering control unit harness connector. Check continuity between combination meter harness connector M24 terminal 30 and power steering control unit harness connector M59 terminal 8. Combination meter Power steering control unit Continuity Connector Terminal Connector Terminal M24 30 M59 8 YES Also check harness for short to ground and short to power. Is the inspection result normal? YES: GO TO 3. NO: Repair or replace damaged parts.
3. CHECK VEHICLE SPEED SIGNAL (COMBINATION METER SIDE) Turn the ignition switch OFF. Connect combination meter harness connector. Check combination meter input/output standard values. Refer to " «REFERENCE VALUE»(ref-592038-S09268436522014010800000) ". Is the inspection result normal? YES: GO TO 4. NO: Replace combination meter. Refer to " «REMOVAL AND INSTALLATION»(ref-592038-S13860149972014010800000) ".
4. CHECK VEHICLE SPEED SIGNAL (POWER STEERING CONTROL UNIT SIDE) Connect power steering control unit harness connector. Turn the ignition switch ON. Check signal between power steering control unit harness connector M59 terminal 8 and ground with oscilloscope. Power steering control unit Value (Approx.) Connector Terminal Condition M59 8 - Ground Vehicle speed: 40 km/h (25 MPH) CAUTION: Check air pressure of tire under standard condition. Also check harness for short to ground and short to power. Is the inspection result normal? YES: Replace power steering control unit. Refer to " «REMOVAL AND INSTALLATION»(ref-592052-S27886428512014010800000) ". NO: GO TO 5.
5. CHECK TERMINALS AND HARNESS CONNECTORS Check power steering control unit pin terminals for damage or loose connection with harness connector. Check combination meter pin terminals for damage or loose connection with harness connector. Is the inspection result normal? YES: Inspection End NO: Repair or replace damaged parts.

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1. CHECK SYSTEM FOR POWER SUPPLY AND GROUND Perform trouble diagnosis for power supply and ground circuit. Refer to " «DIAGNOSIS PROCEDURE»(ref-592052-S18038708942014010800000) ". Is the inspection result normal? YES: GO TO 2. NO: Repair or replace damaged parts.
2. CHECK SYSTEM FOR VEHICLE SPEED SIGNAL Perform trouble diagnosis for vehicle speed signal. Refer to " «DIAGNOSIS PROCEDURE»(ref-592052-S32781627822014010800000) ". Is the inspection result normal? YES: GO TO 3. NO: Repair or replace damaged parts.
3. CHECK SYSTEM FOR ENGINE SPEED SIGNAL Perform trouble diagnosis for engine speed signal. Refer to " «DIAGNOSIS PROCEDURE»(ref-592052-S02873506582014010800000) ". Is the inspection result normal? YES: GO TO 4. NO: Repair or replace damaged parts.
4. CHECK SYSTEM FOR POWER STEERING SOLENOID VALVE Perform trouble diagnosis for power steering solenoid valve. Refer to " «DIAGNOSIS PROCEDURE»(ref-592052-S02680880992014010800000) ". Is the inspection result normal? YES: Perform the symptom diagnosis for the steering system. Refer to " «NVH TROUBLESHOOTING CHART»(ref-592021-S19010864312014010800000) ". NO: Repair or replace damaged parts.