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NO.29 CONSTANT VOLTAGE [L3 Turbo]

id0103b4803500

29 | CONSTANT VOLTAGE
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DESCRIPTION | Incorrect constant voltage
POSSIBLE CAUSE | • Constant voltage circuit malfunction Note • MAP sensor, fuel pressure sensor and accelerator position sensor use constant voltage.

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | Disconnect the MAP sensor connector where constant voltage circuit inspection failed. Turn the ignition switch to the ON position. Measure voltage between the following MAP sensor connector terminals: • Constant voltage terminal - ground terminal Is constant voltage greater than 6.0 V? | Yes | Go to Step 13.
No | Go to the next step.
2 | Is voltage across battery terminals greater than 10.5 V? | Yes | Go to the next step.
No | Inspect the charging system.
3 | Turn the ignition switch off. Leave the MAP sensor connector disconnected. Disconnect the fuel pressure sensor and accelerator position sensor connectors. Measure the voltage between battery positive terminal and ground (between PCM and MAP sensor) circuit at appropriate sensor connector. Is the voltage greater than 10.5 V and within 1.0 V of battery voltage? | Yes | Go to the 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 the ignition switch to the ON position. 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 manifold pressure sensor and PCM connectors. Turn the ignition switch to the ON position. Measure the voltage between PCM terminals, 2Y and 2AB. Is the voltage greater than 10.5 V? | Yes | Go to the next step.
No | Repair open circuit between PCM terminal 2Y and main relay.
6 | Leave the MAP sensor and the PCM connectors disconnected. Measure the resistance between PCM terminals, 2Y and 2AB. Is the resistance greater than 10,000 ohms? | Yes | Inspect for the constant voltage at suspect sensor connector again.
No | Repair the constant voltage circuit short to ground.
7 | Turn the ignition switch off. Leave the MAP sensor disconnected. Disconnect the PCM connector. Measure the resistance between PCM terminal, 1J and constant voltage circuit at appropriate sensor connector. Is the resistance less than 5.0 ohms? | Yes | Inspect for the constant voltage at suspect sensor connector again.
No | Repair the open constant voltage circuit.
8 | Note • Purpose of this step is to determine if WDS or equivalent is communicating with PCM. Reconnect the MAP sensor connector. Turn the ignition switch to the ON position. Access the ECT PID. Can ECT PID be accessed? | Yes | Go to the next step.
No | Go to Step 11.
9 | Are the DTCs present for two or more sensors connected to PCM terminal, 2H? Sensor connected to PCM terminal, 2H. • IAT sensor (P0112, P0113) • Boost air temperature sensor (P0097, P0098) • A/F sensor (P0131, P0132) • HO2S (P0137, P0138) • MAP sensor (P0107, P0108) • ECT sensor (P0117, P0118) • Accelerator position sensor (P2122, P2123, P2127, P2128) | Yes | Go to the next step.
No | Repair the open ground circuit to sensor where 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 ground circuit at appropriate sensor connector and PCM terminal, 2H. Is resistance less than 5.0 ohms? | Yes | Reconnect the sensor connector. Go to appropriate DTC test.
No | Repair open ground circuit.
11 | Turn the ignition switch off. Disconnect the PCM connector. Measure the resistance between battery negative terminal and PCM terminals, 4X, 2AB and 2AC. Is each resistance less than 5.0 ohms? | Yes | Go to the next step.
No | Repair open ground circuit.
12 | Turn the ignition switch off. Measure the resistance between ground circuit at the following sensor connectors and ground: • IAT sensor (integrated in MAF sensor) • Boost air temperature sensor (integrated in MAP sensor) • A/F sensor • HO2S • MAP sensor • ECT sensor • APP sensor | Yes | Ground circuits are normal. Inspect for the constant voltage at suspect sensor connector again.
No | Inspect for the open ground circuit.
13 | Turn the ignition switch off. Disconnect the MAP sensor and integrated the PCM connectors. Turn the ignition switch to the ON position. Measure the voltage between constant voltage circuit at the MAP sensor connector and battery negative terminal. Is the voltage less than 0.5 V? | Yes | Inspect for the constant voltage at suspect sensor connector again.
No | Repair the constant voltage circuit shorted to power in harness.
14 | Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. • If a malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform the repair or diagnosis. - If the vehicle is repaired, troubleshooting is completed. - If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.