NO.26 CONSTANT VOLTAGE [MZR-CD (RF Turbo)]

26	CONSTANT VOLTAGE
DESCRIPTION	• Incorrect constant voltage.
POSSIBLE CAUSE	• Constant voltage circuit malfunction Note • Accelerator pedal position sensor, fuel pressure sensor and boost sensor use constant voltage.


STEP	INSPECTION	RESULTS	ACTION
1	Disconnect the appropriate sensor connectors (the accelerator pedal position sensor, the boost sensor and the fuel pressure sensor) where constant voltage circuits inspection failed. Turn the engine switch to the ON position. Measure the voltage between the following appropriate sensor connector terminals: • Constant voltage terminal and GND terminal. Is constant voltage above 6.0 V?	Yes	Repair constant voltage circuit short to power supply in the wiring harness.
1		No	Go to the next step.
2	Is the voltage across battery terminals above 10.5 V?	Yes	Go to the next step.
2	Is the voltage across battery terminals above 10.5 V?	No	Inspect the charging system.
3	Turn the engine switch off. Leave the appropriate sensor connectors disconnected where constant voltage inspection failed. Measure the voltage between positive terminal and GND circuit at the appropriate sensor vehicle wiring harness connector. Is the voltage above 10.5 V and within 1.0 V of battery voltage?	Yes	Go to the next step.
3		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 engine switch to the ON position. Attempt to access ECT PID. Can ECT PID be accessed?	Yes	Go to Step 7.
4		No	Go to the next step.
5	Turn the engine switch off. Disconnect the accelerator pedal position sensor and the PCM connectors. Turn the engine switch to the ON position. Measure the voltage between PCM connector terminals 104 and 53/79. Is the voltage greater than 10.5 V?	Yes	Go to the next step.
5		No	Repair open circuit between PCM terminal 53/79 and the PCM control relay.
6	Leave the accelerator pedal position sensor and the PCM connectors disconnected. Measure the resistance between the PCM connector terminals 104 and 90. Is the resistance greater than 10,000 ohms?	Yes	Inspect the sensor connector for constant voltage again.
6		No	Repair constant voltage circuit short to GND.
7	Turn the engine switch off. Leave the accelerator pedal position sensor disconnected. Disconnect the PCM connector. Measure the resistance between PCM connector 90 and constant voltage circuit at the appropriate sensor connector. Is the resistance less than 5.0 ohms?	Yes	Inspect sensor connector for constant voltage again.
7		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 appropriate sensor connector. Turn the engine switch to ON. Attempt to access ECT PID. Can ECT PID be accessed?	Yes	Go to the next step.
8		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: • Accelerator pedal position sensor. (P0122, P0123, P0222, P0223). • ECT sensor (P0117, P0118) • Fuel pressure sensor (P0192, P0193) • Fuel temperature sensor (P0182, P0183) • MAF/IAT sensor (P0102, P0103, P0112, P0113) • IAT sensor No.2	Yes	Go to the next step.
9		No	Repair open GND circuit to sensor where constant voltage circuit inspection failed.
10	Turn the engine switch off. Disconnect the WDS or equivalent from the DLC-2. Disconnect the PCM connector. Measure the resistance between GND circuit at the appropriate sensor connector and PCM connector terminal 91. Is the resistance less than 5.0 ohms?	Yes	Reconnect the sensor connector. Go to the applicable DTC inspection. (See DTC TABLE [MZR-CD (RF Turbo)].)
10		No	Repair open GND circuit.
11	Turn the engine switch off. Disconnect the PCM connector. Measure the resistance between battery negative terminal and PCM terminals 65, 85, 103 and 104. Is each the resistance less than 5.0 ohms?	Yes	Go to the next step.
11		No	Repair open GND circuit.
12	Turn the engine switch off. Measure the resistance between GND circuit at the following sensor connector and GND: • Accelerator pedal position sensor • ECT sensor • BARO sensor • Fuel pressure sensor • Fuel temperature sensor • MAF/IAT sensor • IAT sensor No.2 Is the resistance below 5.0 ohms?	Yes	GND circuits are normal. Inspect the sensor connector for constant voltage again.
12		No	Inspect for open GND circuit.
13	Turn the engine switch off. Disconnect the accelerator pedal position sensor. Turn the engine switch to the ON position. Measure the voltage between constant voltage circuit at the accelerator pedal position sensor and battery negative terminal. Is the voltage less than 0.5V?	Yes	Inspect the sensor connector for constant voltage again.
13		No	Repair constant voltage circuit shorted power in wiring harness.
14	Verify test results. • If normal, return to diagnostic index to service any additional symptoms. • If malfunction remains, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)