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

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


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