NO.27 CONSTANT VOLTAGE [L3]

BME010300103265

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 the TP sensor connector where constant voltage circuit inspection failed.
Turn the ignition switch to the ON position.
Measure the voltage between the 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 the next step.
2
Is the 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 TP sensor connector disconnected.
Measure the voltage between battery positive terminal and GND (between PCM and TP 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
• 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.
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 and the PCM connectors.
Turn ignition switch to ON position.
Measure the voltage between PCM connector 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 the main relay.
6
Leave the TP sensor and the PCM connectors disconnected.
Measure the resistance between PCM connector terminals 2Y and 2AB.
Is the resistance greater than 10,000 ohms?
Yes
Inspect for constant voltage at the sensor connector again.
No
Repair the constant voltage circuit short to GND.
7
Turn the ignition switch off.
Leave the TP sensor disconnected.
Disconnect the PCM connector.
Measure the resistance between PCM connector terminal 2K and constant voltage circuit at the appropriate sensor connector.
Is the resistance less than 5.0 ohms?
Yes
Inspect for the constant voltage at the sensor connector again.
No
Repair open 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 to the ON position.
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 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 the next step.
No
Repair open GND 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 GND circuit at appropriate sensor connector and PCM connector terminal 2H.
Is the resistance less than 5.0 ohms?
Yes
Reconnect the sensor connector.
Go to the applicable DTC inspection.
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 4X, 2AB, and 2AC.
Is each resistance less than 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 the 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 normal.
Inspect for constant voltage at the sensor connector again.
No
Inspect for open GND circuit.
13
Turn the ignition switch off.
Disconnect the TP sensor and the PCM connectors.
Turn the ignition switch to the ON position.
Measure the voltage between constant voltage circuit at the TP sensor connector and battery negative terminal.
Is the voltage less than 0.5 V?
Yes
Inspect for constant voltage at the sensor connector again.
No
Repair 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, replace PCM.