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NO.29 CONSTANT VOLTAGE [AJ] (VIN: JMZ LW19J7*# 300001-, JM0 LW10J300 300001-301405, JM6 LW10J300 300001-, JM8 LW28J**# 300001-301513)

BME010300103234

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

  Note

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

Diagnostic procedure

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

  - Constant voltage terminal and GND terminal

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

  Note

  • The purpose of this step is to determine if the WDS or equivalent is communicating with the PCM.

• Turn the ignition switch to the ON position (Engine off).
• Attempt to access ECT PID.
• Can ECT PID be accessed?
Yes
Go to Step 7.
No | Go to the next step.
5 | • Turn the ignition switch off. • Disconnect the TP sensor, the EGR boost sensor and the PCM connectors. • Turn the ignition switch to the ON position (Engine off). • Measure the voltage between PCM connector terminals 71/97 and 24/51/76/77/103.
• Is the voltage above 10.5 V?
Yes
Go to the next step.
No | Repair open circuit between PCM terminal 71/97 and main relay.
6 | • Leave the TP sensor, the EGR boost sensor, the FTP sensor and the PCM connectors disconnected. • Measure the resistance between PCM connector terminals 90 and 24/51/76/77/103. • Is the resistance above 10 kilohms? | Yes | Inspect for the constant voltage at the sensor connector again.
No | Repair the constant voltage circuit shorted to GND.
7 | • Turn the ignition switch off. • Leave the TP sensor disconnected. • Disconnect the PCM connector. • Measure the resistance between PCM connector terminal 90 and the constant voltage circuit at the appropriate sensor connector. • Is the resistance below 5.0 ohms? | Yes | Inspect for the constant voltage at the sensor connector again.
No | Repair open the constant voltage circuit.
8 |

  Note

  • The purpose of this step is to determine if the WDS or equivalent is communicating with the PCM.

• Reconnect the TP sensor connector.
• Turn the ignition switch on.
• Attempt to access ECT PID.
• Can ECT PID be accessed?
Yes
Go to the next step.
No | Go to Step 11.
9 | • Are DTCs present for two or more sensors connected to PCM terminal 91? • Sensor connected to PCM terminal 91:

  - ECT sensor (P0117, P0118, P0125)
  - BARO sensor (P0107, P0108) (European (L.H.D.) specs.)
  - EGR boost sensor (P0106, P0107, P0108) (Australian, General (L.H.D. R.H.D.) specs.)
  - 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 the next step.
No | Repair open GND circuit to sensor where the constant voltage circuit inspection failed.
10 | • Turn the ignition switch off. • Disconnect the WDS or equivalent from the DLC-2. • Disconnect the PCM connector. • Measure the resistance between GND circuit at appropriate sensor connector and PCM connector terminal 91. • Is the resistance below 5.0 ohms? | Yes | Reconnect the sensor connector. Go to the applicable DTC inspection. (See DTC TABLE [AJ] (VIN: JMZ LW19J7*# 300001-, JM0 LW10J300 300001-301405, JM6 LW10J300 300001-, JM8 LW28J**# 300001-301513).)
No | Repair open GND circuit.
11 | • Turn the ignition switch off. • Disconnect the PCM connector. • Measure the resistance between battery negative terminal and PCM terminals 24/51/76/77/103. • Is each resistance below 5.0 ohms? | Yes | Go to the next step.
No | Repair open GND circuit.
12 | • Turn the ignition switch off. • Measure the 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 the constant voltage at the sensor connector again.
No | Inspect for open GND circuit.
13 | • Turn the ignition switch off. • Disconnect the TP sensor, the EGR boost sensor, the FTP sensor and the PCM connectors. • Turn the ignition switch to the ON position (Engine off). • Measure the voltage between the constant voltage circuit at TP sensor connector and battery negative terminal.
• Is the voltage below 0.5 V?
Yes
Inspect for the constant voltage at the sensor connector again.
No | Repair the constant voltage circuit shorted to power in the wiring 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 the PCM.