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NO.27 CONSTANT VOLTAGE [L3]

BME010300000W29

27 | CONSTANT VOLTAGE
--- | ---
DESCRIPTION | Incorrect constant voltage
POSSIBLE CAUSE | • Constant voltage circuit malfunction

  Note

  • TP sensor uses constant voltage.

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
--- | --- | --- | ---
1 | Disconnect TP sensor connector where constant voltage circuit inspection failed. Turn ignition switch to ON position. Measure voltage between following TP sensor connector terminals: • Constant voltage terminal - GND terminal Is constant voltage greater than 6.0 V? | Yes | Go to Step 13.
No | Go to next step.
2 | Is voltage across battery terminals greater than 10.5 V? | Yes | Go to next step.
No | Inspect charging system.
3 | Turn ignition switch off. Leave TP sensor connector disconnected. Measure voltage between battery positive terminal and GND (between PCM and TP sensor) circuit at appropriate sensor connector. Is voltage greater than 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 position.
Attempt to access ECT PID.
Can ECT PID be accessed?

Yes
Go to Step 7.
No | Go to next step.
5 | Turn ignition switch off. Disconnect TP sensor and PCM connectors. Turn ignition switch to ON position. Measure voltage between PCM connector terminals 2Y and 2AB. Is voltage greater than 10.5 V? | Yes | Go to next step.
No | Repair open circuit between PCM terminal 2Y and main relay.
6 | Leave TP sensor and PCM connectors disconnected. Measure resistance between PCM connector terminals 2Y and 2AB. Is resistance greater than 10,000 ohms? | Yes | Inspect for constant voltage at suspect sensor connector again.
No | Repair constant voltage circuit short to GND.
7 | Turn ignition switch off. Leave TP sensor disconnected. Disconnect PCM connector. Measure resistance between PCM connector terminal 2K and constant voltage circuit at appropriate sensor connector. Is resistance less than 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 to ON position.
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 2H? Sensor connected to PCM terminal 2H: • IAT sensor (P0112, P0113) • FHO2S (P0131, P0132) • RHO2S (P0138)
• Barometric pressure sensor (P2228, P2229)
• Manifold absolute pressure sensor (P0107, P0108)
• ECT sensor (P0117, P0118)
• TP sensor (P0122, P0123)
• TFT sensor (P0712, P0713)
Yes
Go to next step.
No | Repair open GND circuit to sensor where constant voltage circuit inspection failed.
10 | Turn ignition switch off. Disconnect WDS or equivalent from DLC-2. Disconnect PCM connector. Measure resistance between GND circuit at appropriate sensor connector and PCM connector terminal 2H. Is resistance less than 5.0 ohms? | Yes | Reconnect sensor connector. Go to appropriate DTC test.
No | Repair open GND circuit.
11 | Turn ignition switch off. Disconnect PCM connector. Measure resistance between battery negative terminal and PCM terminals 4X, 2AB, and 2AC. Is each resistance less than 5.0 ohms? | Yes | Go to next step.
No | Repair open GND circuit.
12 | Turn ignition switch off. Measure resistance between GND circuit at following sensor connector and GND: • IAT sensor (integrated in MAF sensor) • FHO2S • RHO2S
• Barometric pressure sensor
• Manifold absolute pressure sensor
• ECT sensor
• TP sensor
• TFT sensor
Yes
GND circuits are okay.
Inspect for constant voltage at suspect sensor connector again.
No | Inspect for open GND circuit.
13 | Turn ignition switch off. Disconnect TP sensor and PCM connectors. Turn ignition switch to ON position. Measure voltage between constant voltage circuit at TP sensor connector and battery negative terminal. Is voltage less than 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 okay, return to diagnostic index to service any additional symptoms. • If malfunction remains, replace PCM.