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Steering Control System: Overview Infiniti QX50 I

Steering Control Systems 4 illustrations ~731 words

Component Description

Component partsReference/Function
Power steering control unitSignals from various sensors control the driving voltage to the power steering solenoid valve. The power steering control unit controls the driving voltage to the power steering solenoid valve for maintaining the power steering assist force when the fail-safe function is activated. (The engine speed signals control EPS system if any vehicle speed signal error is detected.)
Unified meter and A/C amp." DESCRIPTION "
ECM" DESCRIPTION "
Power steering solenoid valve" DESCRIPTION "

Description

Power supply to EPS system

Power steering solenoid valve controls the power steering oil pressure in the gear housing assembly.

ECM sends engine speed signal to power steering control unit.

Scheme 1

Scheme 1: Diagnosis Procedure
Scheme 1: Diagnosis Procedure

Scheme 2

Scheme 2
Scheme 2
  1. PERFORM ECM SELF-DIAGNOSIS With CONSULT Turn the ignition switch ON. Perform "ENGINE" self-diagnosis. Refer to " «CONSULT FUNCTION»(ref-616999-S11342544512014052000000) ". Is any DTC detected? YES: Check the DTC. NO: GO TO 2.
  2. CHECK HARNESS BETWEEN ECM AND POWER STEERING CONTROL UNIT Turn the ignition switch OFF. Disconnect ECM harness connectors. Disconnect power steering control unit harness connector. Check continuity between ECM harness connector and power steering control unit harness connector. ECM Power steering control unit Continuity Connector Terminal Connector Terminal M107 110 M108 10 Existed Check continuity between power steering control unit harness connector and ground. Power steering control unit - Continuity Connector Terminal M108 10 Ground Not existed Is the inspection result normal? YES: GO TO 3. NO: Repair or replace damaged parts.
  3. CHECK ENGINE SPEED SIGNAL (1) Connect ECM harness connectors. Check signal between ECM harness connector and ground with oscilloscope. ECM - Condition Voltage (Approx.) Connector Terminal M107 110 Ground Engine is running Warm-up condition Idle speed Engine is running Warm-up condition Engine speed: Approx. 2, 000 rpm Is the inspection result normal? YES: GO TO 4. NO: Replace ECM. Refer to " «ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT (ECM): DESCRIPTION»(ref-616999-S11044644322014052000000) ".
  4. CHECK ENGINE SPEED SIGNAL (2) Turn the ignition switch OFF. Connect power steering control unit harness connector. Check signal between power steering control unit harness connector and ground with oscilloscope. Power steering control unit - Condition Voltage (Approx.) Connector Terminal M108 10 Ground Engine is running Warm-up condition Idle speed Engine is running Warm-up condition Engine speed: Approx. 2, 000 rpm Is the inspection result normal? YES: GO TO 5. NO: Replace power steering control unit. Refer to " «EXPLODED VIEW»(ref-617054-S27098831112014052000000) ".
  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.

Unified meter and A/C amp. sends vehicle speed signal to power steering control unit.

Scheme 3

Scheme 3: Diagnosis Procedure
Scheme 3: Diagnosis Procedure
  1. PERFORM UNIFIED METER AND A/C AMP. SELF-DIAGNOSIS With CONSULT Turn the ignition switch ON. Perform "METER/M&A" self-diagnosis. Refer to " «CONSULT FUNCTION (METER/M&A)»(ref-617020-S31032987262014052000000) ". Is any DTC detected? YES: Check the DTC. NO: GO TO 2.
  2. CHECK HARNESS BETWEEN UNIFIED METER AND A/C AMP. AND POWER STEERING CONTROL UNIT Turn the ignition switch OFF. Disconnect unified meter and A/C amp. harness connector. Disconnect power steering control unit harness connector. Check continuity between unified meter and A/C amp. harness connector and power steering control unit harness connector. Unified meter and A/C amp. Power steering control unit Continuity Connector Terminal Connector Terminal M66 8 M108 8 Existed Check continuity between power steering control unit harness connector and ground. Power steering control unit - Continuity Connector Terminal M108 8 Ground Not existed Is the inspection result normal? YES: GO TO 3. NO: Repair or replace damaged parts.
  3. CHECK VEHICLE SPEED SIGNAL (1) Connect unified meter and A/C amp. harness connector. Check unified meter and A/C amp. input/output standard values. Refer to " «REFERENCE VALUE»(ref-617020-S15268019342014052000000) ". Is the inspection result normal? YES: GO TO 4. NO: Replace unified meter and A/C amp. Refer to " «EXPLODED VIEW»(ref-617020-S29147897522014052000000) ".
  4. CHECK VEHICLE SPEED SIGNAL (2) Turn the ignition switch OFF. Connect power steering control unit harness connector. Check signal between power steering control unit harness connector and ground with oscilloscope. Power steering control unit - Condition Voltage (Approx.) Connector Terminal M108 8 Ground Vehicle speed: 40 km/h (25 MPH) CAUTION: Check air pressure of tire under standard condition. NOTE: The maximum voltage varies depending on the specification (destination unit). Is the inspection result normal? YES: GO TO 5. NO: Replace power steering control unit. Refer to " «EXPLODED VIEW»(ref-617054-S27098831112014052000000) ".
  5. CHECK TERMINALS AND HARNESS CONNECTORS Check power steering control unit pin terminals for damage or loose connection with harness connector. Check unified meter and A/C amp. pin terminals for damage or loose connection with harness connector. Is the inspection result normal? YES: INSPECTION END NO: Repair or replace damaged parts.

Scheme 4

Scheme 4: TERMINAL LAYOUT
Scheme 4: TERMINAL LAYOUT
  1. Hard steering when fully turning the steering wheel.
  2. Light steering when driving at a high speed.

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