P1639

DTC P1639 Reference Voltage # 2 Circuit Fault




Circuit Description
The AP sensor # 1 shares a 5 Volt reference with the PCM.

If the PCM detects the 5 Volt reference for the AP sensor # 1 is failure, DTC P1635 will be set.

Conditions for setting the DTC
- The ignition is "ON".
- The 5 Volt reference voltage for the AP sensor # 1 is less than 4 volts.
- The 5 Volt reference voltage for the AP sensor # 1 is more than 5 volts.

Action Taken When the DTC Sets
- The PCM will not illuminate the malfunction indicator lamp (MIL).
- The PCM will store condition which were present when the DTC was set as Freeze Frame and in the Failure Records data.

Conditions for Clearing the MIL/DTC
- The PCM will turn the MIL "OFF" on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
- A history DTC P1639 will clear after 40 consecutive trip cycle during which the warm up cycles have occurred without a fault.
- DTC P1639 can be cleared using the Tech 2 "Clear Info" function or by disconnecting the PCM battery feed.

Steps 1 - 3:

Steps 4 - 6:

Test Description