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Home >> Mazda >> 2007 >> B4000 SE, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 70 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0340: Camshaft Position Sensor Malfunction >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Mazda B4000, 2003 Mazda B3000, and 2003 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.
  1. If QUICK TEST was not performed, go to QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed and engine starts, go to next step. If QUICK TEST was performed and engine does not start, DTC P0340 is not causing no start condition. See NO START  testing under SYSTEM TESTS.
  2. Clear & Attempt To Regenerate DTC P0340 -  Clear DTCs using PCM Reset Procedure. See CLEARING CODES  under RETRIEVING DIAGNOSTIC TROUBLE CODES. With KOER, increase engine speed to more than 1500 RPM for 10 seconds. Repeat 2 times. Turn ignition off. Using scan tool, retrieve Continuous Memory DTCs. If DTC P0340 is set, go to next step. If DTC P0340 is not set, fault is intermittent. See INTERMITTENT  testing under SYSTEM TESTS.
  3. Check For Open CMP Circuit Between PCM & CMP Sensor -  Disconnect PCM 104-pin harness connector and CMP sensor 2-pin harness connector. Connect Breakout Box (49-UN01-130) to PCM harness connector only. See Figure . Measure resistance of CMP circuit (Dark Blue/Orange wire) between breakout box terminal No. 85 and CMP sensor harness connector. See Fig 1 . Record reading. Measure resistance of SIG RTN circuit (Green/Red wire) between breakout box terminal No. 91 and CMP sensor harness connector. See Fig 1 . Record reading. If each resistance reading is less than 5 ohms, go to next step. If either resistance reading is 5 ohms or more, repair open circuit. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  8 .
    Fig 1: Identifying CMP Sensor Harness Connector Circuits
    G00155539Courtesy of MAZDA MOTORS CORP.
  4. Check CMP For Short To Power -  Reconnect CMP sensor harness connector. With KOEO, measure voltage between breakout box terminal No. 85 (CMP circuit) and terminals No. 51 and 103 (PWR GND circuits). Turn ignition off. If voltage is less then one volt, go to next step. If voltage is one volt or more, repair short circuit. After repair, go to step  8 .
  5. Check CMP For Short To GND -  Disconnect CMP sensor harness connector. Measure resistance between breakout box terminals No. 85 (CMP circuit) and 91 (SIG RTN circuit). If resistance reading is more than 10,000 ohms, go to next step. If resistance reading is 10,000 ohms or less, repair short circuit in Dark Blue/Orange wire between PCM 104-pin harness connector terminal No. 85 and CMP sensor harness connector. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
  6. Check For Shorts In PCM -  Connect PCM to breakout box 104-pin harness connector. Disconnect CMP sensor harness connector. Measure resistance between CMP and SIG RTN circuits at CMP sensor. If resistance reading is more than 500 ohms, go to next step. If resistance reading is 500 ohms or less, replace faulty PCM. After repair, go to step  8 .
  7. Check CMP Sensor Output -  Reconnect CMP harness sensor connector. Set DVOM to AC scale to monitor less than 5 volts. Measure voltage between breakout box terminals No. 85 (CMP circuit) and 103 (PWR GND circuit) while running engine at varying RPM. If AC voltage varies more than 0.1 volt, replace faulty PCM. After repair, go to next step. If AC voltage reading does not vary more then 0.1 volt, replace faulty CMP sensor. After repair, go to next step.
  8. Verify Trouble Shooting Of DTCs Completed -  Make sure all electrical connectors are reconnected. Clear DTCs from PCM memory using scan tool. Perform QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If the same DTC is present, replace faulty PCM. Repeat QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, see DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no DTCs are present, test is complete.
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