P1618
P1618 - Sensor Reference Voltage 1, Erratic
For wiring diagrams, refer to.
• When Monitored: With the ignition on.
• Set Condition: The PCM detects that the 5 volt supply circuit voltage is not within a specific range based on operating conditions. One trip fault. ETC light is flashing.
• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure
Test Step 1 - DTC is Active
• Improperly installed aftermarket accessories can cause this DTC to set. Check for any improperly installed aftermarket accessories before continuing with this test.
• Start the engine and allow it to idle for at least 60 seconds.
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
• With a scan tool, select view DTCs.
Is the status active for this DTC?
Yes
• Go to Test Step 2 => [ Test
Step 2 - 5 Volt Supply Circuit Shorted to Voltage ]
No
• Refer to the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC
Test Step 2 - 5 Volt Supply Circuit Shorted to Voltage
• Turn the ignition OFF.
• Disconnect the connector from each sensor or component that shares the 5 volt supply.
• Disconnect all of the PCM connectors.
• Turn the ignition ON.
• Measure the voltage of the 5 volt supply circuit.
Is there any voltage present?
Yes
• Repair the 5 volt supply circuit for a short to voltage.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 3 => [ Test
Step 3 - 5 Volt Supply Circuit Shorted to Ground ]
Test Step 3 - 5 Volt Supply Circuit Shorted to Ground
• Turn the ignition OFF.
• Measure the resistance between ground and the 5 volt supply circuit.
Is the resistance less than 100 ohms?
Yes
• Repair the 5 volt supply circuit for a short to ground.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 4 => [ Test
Step 4 - 5 Volt Supply Circuit Voltage ]
Test Step 4 - 5 Volt Supply Circuit Voltage
• Turn the ignition OFF.
• Connect all of the PCM connectors.
• Turn the ignition ON.
• Measure the voltage on the 5 volt supply circuit.
Is the voltage between 4.8 and 5.2 volts?
Yes
• Go to Test Step 5 => [ Test
Step 5 - Sensor Shorted Internally ]
No
• Go to Test Step 6 => [ Test
Step 6 - Checking the PCM Power and Ground Circuits ]
Test Step 5 - Sensor Shorted Internally
• Turn the ignition OFF.
You must turn the ignition OFF when connecting or disconnecting each sensor or component connector, then turn the ignition ON when measuring the circuit voltage.
• One at a time, connect each sensor or component connector that shares the 5 volt supply circuit. After connecting each component, turn the ignition on and measure the voltage of the 5 volt supply circuit.
Is the voltage more than 5.1 volts or less than 4.9 volts when connecting any of the sensors?
Yes
• Replace the internally shorted sensor or component.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 6 => [ Test
Step 6 - Checking the PCM Power and Ground Circuits ]
Test Step 6 - Checking the PCM Power and Ground Circuits
• Perform the diagnostic procedure for Checking the PCM Power and Ground Circuits. Refer to => Non-DTC Based Diagnostics. PCM Power and Ground Circuit Test
Were any problems found?
Yes
• Repair the PCM power and ground circuits as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 7 => [ Test
Step 7 - PCM ]
Test Step 7 - PCM
• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between all applicable components and the PCM.
• Look for any chafed, pierced, pinched, or partially broken wires.
• Look for broken, bent, pushed out or corroded terminals.
• Refer to any technical service bulletins that may apply.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Replace and program the PCM.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test