DTC P1496: 5-Volt Supply Output Too Low: Testing

NOTE: Vehicles equipped with a 2.7L engine are equipped with a Manifold Absolute Pressure (MAP) sensor. Vehicles equipped with a 3.2L and 3.5L engine are equipped with an Intake Air Temperature/Manifold Absolute Pressure (IAT/MAP) sensor. For this test, IAT/MAP will be identified as MAP sensor.

Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed and equal to zero, go to next step. If GOOD TRIP counter is not displayed and equal to zero, go to step 9 .
Turn ignition off. Disconnect Throttle Position (TP) sensor connector. Turn ignition on. Measure voltage between ground and 5-volt supply circuit (Violet/White wire) at TP sensor harness connector. If voltage is less than 4.5 volts, go to next step. If voltage is 4.5 volts or more, go to step 8 .
With voltmeter still connected between ground and Violet/White wire at TP sensor harness connector, turn ignition off. Disconnect MAP sensor harness connector. See Figure or Figure . Turn ignition on. If voltage does not change from less than 4.5 volts to more than 4.5 volts, go to next step. If voltage changes from less than 4.5 volts to more than 4.5 volts, replace MAP sensor.
NOTE: A/C pressure sensor may also be referred to as A/C pressure transducer.
With voltmeter still connected between ground and Violet/White wire at TP sensor harness connector, turn ignition off. Disconnect A/C pressure sensor Gray connector. A/C pressure sensor is located in high pressure line, near A/C compressor. Turn ignition on. If voltage does not change from less than 4.5 volts to more than 4.5 volts, go to next step. If voltage changes from less than 4.5 volts to more than 4.5 volts, replace A/C pressure sensor.
With voltmeter still connected between ground and Violet/White wire at TP sensor harness connector, turn ignition off. Disconnect EGR solenoid harness connector. EGR solenoid is integral to EGR valve. EGR valve is mounted to rear of right cylinder head. Turn ignition on. If voltage does not change from less than 4.5 volts to more than 4.5 volts, go to next step. If voltage changes from less than 4.5 volts to more than 4.5 volts, replace EGR valve.
Turn ignition off. Ensure TP sensor, EGR solenoid, A/C pressure sensor and MAP sensor connectors are disconnected. Disconnect PCM harness connectors. See Figure . Measure resistance between ground and Violet/White wire at TP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Violet/White wire.
If no other possible causes are remaining, PCM is assumed to be defective. Replace PCM.
Turn ignition off. Reconnect TP sensor connector. Disconnect MAP sensor connector. See Figure or Figure . Turn ignition on. Measure voltage between ground and Violet/White wire at MAP sensor harness connector. If voltage is 4.5 volts or more, go to next step. If voltage is less than 4.5 volts, replace TP sensor.
Conditions that set DTC are not present at this time. Perform the following to help identify intermittent condition:
- With engine running at normal operating temperature, wiggle related wiring harness while monitoring related parameters on scan tool. If voltage changes or DTC sets while wiggling wiring harness, repair connectors or wiring harness where wiggling caused voltage to change or DTC to set.
- Review freeze frame information on scan tool. Duplicate conditions present when DTC was set.
- Refer to any technical service bulletins that may apply.
- Visually inspect related wiring harness. Check for chafed, pierced, pinched or partially broken wires.
- Visually inspect related wiring harness connectors. Check for broken, bent, pushed out or corroded terminals.
If a problem is found, repair as necessary. If no problems are found, test is complete.