Installed new engine and car runs good and it is crisp. It has heads, cam, LT headers with no cats (99 6spd). I will have it dyno tune(LS-1 edit) on Tuesday. I could clear every code on the DIC except codes: P1635 (5 volt reference #1 Circuit -B) and P1639 (5 volt reference #2 Circuit -B). What are those codes and how can I fix it before Tuesday.
Thanks for all your help! :(

 

According to the 2003 service manual, the PCM provides +5 volts to following sensors:

manifold absolute pressure (MAP)
engine oil pressure (EOP)
air conditioning pressure sensor
fuel tank pressure sensor (FTP)

Out of spec deviation on the EOP and/or MAP circuit will set P1635 and out spec deviation on the A/C pressure sensor and/or FTP will set P1639. The circuit condition on one sensor can affect the circuit on another, resulting in a set DTC code. You could have a loose connection, short, defective senor or bad PCM.

 

P1635:
CIRCUIT DESCRIPTION
The PCM uses a common 5 volt Reference 1 circuit as a sensor teed. This circuit supplies 5 volts to the following sensors:


The MAP sensor
The Engine Oil Pressure sensor
The PCM monitors the voltage on the 5 volt Reference 1 circuit. If the voltage is out of range, this DTC sets.

CONDITIONS FOR RUNNING THE DTC
The engine is operating.

CONDITIONS FOR SETTING THE DTC


The 5 volt reference circuit is out of range.
The above condition is present for greater than 2 seconds .
ACTION TAKEN WHEN THE DTC SETS


The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The PCM records the operating conditions at the time the diagnostic fails. The first Time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC


The PCM turns the malfunction indicator lamp (MIL) OFF after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A last test failed (current DTC) clears when the diagnostic runs and does not fail.
A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
Use a scan tool in order to clear the MIL/DTC.
DIAGNOSTIC AIDS

IMPORTANT:


Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the module. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM.
For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616-A. Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Diagrams. For an intermittent condition, refer to Symptoms. See: Symptoms
TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.


The 5 volt reference circuits for the sensors are connected together inside the PCM. Both DTCs P1635 and P1639 set at the same time, indicates a 5 reference circuit is shorted to a voltage.
The 5 volt reference circuits for the sensors are connected together inside the PCM. When only P1635 is set, this indicates a short to ground on one of the 5 volt reference circuits.
This step isolates the 5 volt reference circuit from the sensor signal circuit.
This step determines if the 5 volt reference circuits or the fuel level sensor signal circuit are only shorted when the fuel pump is enabled. You may have to enable the fuel pump a couple of times to see if the voltages increase. Inspect the fuel pump harness thoroughly for being shorted to the fuel tank pressure sensor and/or the fuel level sensors.
The 5 volt reference circuits may be shorted to another PCM circuit. The shorted circuit may not be apparent when the PCM harness connector is disconnected. Testing continuity from each 5 volt reference circuit isolates the shorted circuit. For detailed circuit information, refer to Full page schematics.
For detailed circuit information, refer to the Full Page Schematic.

P1639:
CIRCUIT DESCRIPTION
The PCM uses a common 5 volt Reference 2 circuit as a sensor feed. This circuit supplies 5 volts to the following sensors:


The Fuel Tank Pressure sensor
The A/C Refrigerant Pressure sensor
The PCM monitors the voltage on the 5 volt Reference circuit. If the voltage is out of range, this DTC sets.

CONDITIONS FOR RUNNING THE DTC
The engine operating.

CONDITIONS FOR SETTING THE DTC


The 5 volt reference circuit is out of range.
The above condition is present for greater than 2 seconds .
ACTION TAKEN WHEN THE DTC SETS


The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC


The PCM turns the malfunction indicator lamp (MIL) OFF after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A last test failed (current DTC) clears when the diagnostic runs and does not fail.
A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
Use a scan tool in order to clear the MIL/DTC.
DIAGNOSTIC AIDS

IMPORTANT:


Remove any debris from the PCM/TAC module connector surfaces before servicing the PCM/TAC module. Inspect the PCM/TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM/TAC modules.
For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616-A. Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Diagrams.
A fuel level sensor (right tank) signal circuit that is shorted to B+ may set this DTC.
For an intermittent condition, refer to Symptoms. See: Symptoms
TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.


The 5 volt reference circuits for the sensors are connected together inside the PCM. Both DTCs P1635 and P1639 set at the same time, indicates a 5 volt reference circuit is shorted to a voltage.
The 5 reference circuits for the sensors are connected together inside the PCM. When only P1639 is set, this indicates a short to ground on one of the 5 reference circuits for the A/C Refrigerant Pressure sensor or the Fuel Tank Pressure sensor.
This step determines if a 5 volt reference circuit is shorted to ground.
The 5 volt reference circuits may be shorted to another PCM circuit. The shorted circuit may not be apparent when the PCM harness connector is disconnected. Testing continuity from each 5 volt reference circuit isolates the shorted circuit.