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NO.29 CONSTANT VOLTAGE [AJ] (VIN: JM0 LW10J300 301406-, JMZ LW69J7*# 307683-, JM8 LW28J**# 301514-, JM8 LW28A**# 301514- (Assumed))

BME010300000W16

29 | Constant voltage
DESCRIPTION | • Incorrect constant voltage
POSSIBLE CAUSE | • Constant voltage circuit malfunction

  Note

  • TP sensor, EGR boost sensor and FTP sensor use constant voltage.

Diagnostic procedure

STEP | INSPECTION | ACTION
--- | --- | ---
1 | • Disconnect appropriate sensor connector when constant voltage circuit inspection failed. • Turn ignition switch to ON (Engine OFF). • Measure voltage between following appropriate sensor connector terminals:

  - Constant voltage terminal and GND terminal

• Is constant voltage above 6.0 V?
Yes
Go to Step 13.
No | Go to next step.
2 | • Is voltage across battery terminals above 10.5 V? | Yes | Go to next step.
No | Inspect charging system.
3 | • Turn ignition switch to OFF. • Leave appropriate sensor connector disconnected. • Measure voltage between battery positive terminal and GND (between PCM and appropriate sensor) circuit at appropriate sensor connector. • Is voltage above 10.5 V and within 1.0 V of battery voltage? | Yes | Go to next step.
No | Go to Step 8.
4 |

  Note

  • Purpose of this step is to determine if WDS or equivalent is communicating with PCM.

• Turn ignition switch to ON (Engine OFF).
• Attempt to access ECT PID.
• Can ECT PID be accessed?
Yes
Go to Step 7.
No | Go to next step.
5 | • Turn ignition switch to OFF. • Disconnect TP sensor, EGR boost sensor and PCM connectors. • Turn ignition switch to ON (Engine OFF). • Measure voltage between PCM connector terminals 34/60 and 6/22/23/25/100. • Is voltage above 10.5 V? | Yes | Go to next step.
No | Repair open circuit between PCM terminal 71/97 and main relay.
6 | • Leave TP sensor, EGR boost sensor, FTP sensor and PCM connectors disconnected. • Measure resistance between PCM connector terminals 33 and 6/22/23/25/100. • Is resistance above 10 kilohms? | Yes | Inspect for constant voltage at suspect sensor connector again.
No | Repair constant voltage circuit shorted to GND.
7 | • Turn ignition switch off. • Leave TP sensor disconnected. • Disconnect PCM connector. • Measure resistance between PCM connector terminal 33 and constant voltage circuit at appropriate sensor connector. • Is resistance below 5.0 ohms? | Yes | Inspect for constant voltage at suspect sensor connector again.
No | Repair open constant voltage circuit.
8 |

  Note

  • Purpose of this step is to determine if WDS or equivalent is communicating with PCM.

• Reconnect TP sensor connector.
• Turn ignition switch on.
• Attempt to access ECT PID.
• Can ECT PID be accessed?
Yes
Go to next step.
No | Go to Step 11.
9 | • Are DTCs present for two or more sensors connected to PCM terminal 20? • Sensor connected to PCM terminal 20:

  - ECT sensor (P0117, P0118, P0125)
  - BARO sensor (P2227, P2228.P2229) or (P2228,P2229)
  - HO2S (front) (P0131, P0132, P0134, P0151, P0152, P0154)
  - HO2S (rear) (P0138, P0140, P0158, P0160)
  - IAT sensor (P0111, P0112, P0113)
  - TP sensor (P0121, P0122, P0123)

Yes
Go to next step.
No | Repair open GND circuit to sensor where constant voltage circuit inspection failed.
10 | • Turn ignition switch to OFF. • Disconnect WDS or equivalent from DLC-2. • Disconnect PCM connector. • Measure resistance between GND circuit at appropriate sensor connector and PCM connector terminal 20. • Is resistance below 5.0 ohms? | Yes | Reconnect sensor connector. Go to appropriate DTC test.
No | Repair open GND circuit.
11 | • Turn ignition switch to OFF. • Disconnect PCM connector. • Measure resistance between battery negative terminal and PCM terminals 6/22/23/25/100. • Is each resistance below 5.0 ohms? | Yes | Go to next step.
No | Repair open GND circuit.
12 | • Turn ignition switch to OFF. • Measure resistance between GND circuit at following sensor connector and GND:

  - TP sensor
  - EGR boost sensor
  - ECT sensor
  - IAT sensor
  - HO2S (front)
  - HO2S (rear)

• Is each resistance below 5.0 ohms?
Yes
GND circuits are normal.
Inspect for constant voltage at suspect sensor connector again.
No | Inspect for open GND circuit.
13 | • Turn ignition switch to OFF. • Disconnect TP sensor, EGR boost sensor, FTP sensor and PCM connectors. • Turn ignition switch to ON (Engine OFF). • Measure voltage between constant voltage circuit at TP sensor connector and battery negative terminal.
• Is voltage below 0.5 V?
Yes
Inspect for constant voltage at suspect sensor connector again.
No | Repair constant voltage circuit shorted to power in harness.
14 | • Verify test results.

  - If normal, return to diagnostic index to service any additional symptoms.
  - If malfunction remains, inspect related Service Information and perform repair or diagnosis.

  • If vehicle is repaired, troubleshooting completed.
  • If vehicle is not repaired or additional diagnostic information is not available, replace or reprogram PCM.