Diagnostic Procedure

WARNING: This page is about a different car, the 2005 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.

CHECK ATP SWITCH SIGNAL
With CONSULT-II
1. Start engine.
2. Select "DATA MONITOR" mode for "ALL MODE AWD/4WD" with CONSULT-II.
3. Read out the value of "ATP SWITCH".
  
  Fig 1: Checking ATP Switch Signal
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Fig 2: Identifying "ATP SWITCH" On Data Monitor Screen
  Courtesy of NISSAN MOTOR CO., U.S.A.
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector terminal and ground.
  
  Fig 3: Transfer Control Unit Harness Connector Terminal And Ground Voltage Specification
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Fig 4: Checking Voltage Between Transfer Control Unit Harness Connector Terminal And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 5.
2. NG: GO TO 2.
CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND ATP SWITCH
1. Turn ignition switch "OFF". (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the ATP switch harness connector.
3. Check continuity between transfer control unit harness connector E143 terminal 40 (L) and ATP switch harness connector F55 terminal 8 (L/Y).
  1. Continuity should exist.
  Also check harness for short to ground and short to power.
OK or NG
1. OK: GO TO 3.
2. NG: Repair or replace damaged parts.
Fig 5: Checking Continuity Between Transfer Control Unit Harness Connector E143 Terminal 40 And ATP Switch Harness Connector F55 Terminal 8
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK GROUND CIRCUIT
1. Turn ignition switch "OFF". (Stay for at least 5 seconds.)
2. Disconnect ATP switch harness connector.
3. Check continuity between ATP switch harness connector F55 terminal 9 (B) and ground.
  1. Continuity should exist.
  Also check harness for short to ground and short to power.
OK or NG
1. OK: GO TO 4.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
Fig 6: Checking Continuity Between ATP Switch Harness Connector F55 Terminal 9 (B) And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK ATP SWITCH
1. Turn ignition switch "OFF". (Stay for at least 5 seconds.)
2. Disconnect ATP switch harness connector.
3. Remove ATP switch. Refer to "LOCATION OF ELECTRICAL PARTS ".
4. Push and release ATP switch and check continuity between ATP switch terminals 8 and 9.
  
  Fig 7: ATP Switch Terminals 8 And 9 Continuity Specifications
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 5.
2. NG: Replace ATP switch. Refer to "LOCATION OF ELECTRICAL PARTS ".
Fig 8: Checking Continuity Between ATP Switch Terminals 8 And 9
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to "TRANSFER CONTROL UNIT INPUT/OUTPUT SIGNAL REFERENCE VALUES ".

OK or NG
1. OK: GO TO 6.
2. NG: Check transfer control unit pin terminals for damage or loose connection with harness connector. If any items are damaged, repair or replace damaged parts.
CHECK ATP WARNING LAMP
1. Turn ignition switch "ON". (Do not start engine.)
2. Move A/T selector lever to "P" position.
3. Set 4WD shift switch from "4H" to "4LO" or "4LO" to "4H".
Does ATP warning lamp turn ON while switching?
1. YES: GO TO "ATP WARNING LAMP TURNS ON ".
2. NO: Inspection End.