Page 1460 of 2100

6E±493
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1571 Brake Switch No Operation
060R200067
Circuit Description
The brake switch has 3 functions.
Brake pedal operation check
Brake light operation (On and off)
Cruise control (Cancel)
The PCM receives vehicle speed and switch position
signals from the brake switch. The PCM sets brake
operating conditions in response to these signals.
If the brake switch is on, the brake system is in normal
operation (cruise control cancelled).
Conditions for Setting the DTC
Two break switch signals do not acknowledge after
signal changed.
Switch does not change during accelerating vehicle or
decelerating.
VSS is not fault.
Engine is running.
Action Taken When the DTC Sets
The PCM will not turn the malfunction indicator lamp
(MIL) ªONº.
The PCM will store conditions which were present
when the DTC was set as Failure Records only. This
information will not be stored as Freeze Frame data.
Conditions for Clearing the DTC
DTC P1571 can be cleared by using the scan tool
ªClear Infoº function or by disconnecting the PCM
battery feed.
Diagnostic Aids
Damaged harness±Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
fuel level display on the scan tool while moving
connectors and wiring harnesses related to the sensor.
A change in the display will indicate the location of the
fault.
Page 1461 of 2100

6E±494
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P1571 Brake Switch No Operation
StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªOffº.
Engine ªOffº.
2. Check following fuses.
BACK 15A
STOP LAMP 15A
Was a problem found?
ÐVerify repairGo to Step 3
31. Make adjustment to the brake switch.
(Refer to
ªBrake switchº in ª10A CRUISE
CONTROL SYSTEMº.
)
Was the problem found?
ÐVerify repairGo to Step 4
41. Push the shaft on brake switch.
2. Check shaft operation for smooth movement.
Was the problem found?
ÐVerify repairÐ
51. Disconnect the connector at brake switch.
2. Check following terminal pin by ohmmeter.
(Leave the shaft position at brake switch. Don't
push it.)
Between pin 1 and pin 2
Between pin 3 and pin 4
Was it specified value?
Between pin1
and pin2 is
0, Between
pin3 and pin4
is 8
Go to Step 6Go to Step 9
61. Disconnect the connector at brake switch.
2. Check following terminal pin at ohmmeter.
(Don't press the button of the brake switch.)
wBetween pin 1 and pin 2
wBetween pin 3 and pin 4
Was it specified value?
Between pin1
and pin2 is
8, Between
pin3 and pin4
is 0
Go to Step 7Go to Step 9
71. Probe related circuits for open or short to ground.
2. If a problem was found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 8
81. Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
On-Vehicle Service in
Powertrain Control Module and Sensors for
procedures.
And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Was the action completed?
ÐVerify repairÐ
91. Replace the brake switch.
Was the action completed?
ÐVerify repairÐ
Page 1462 of 2100

6E±495
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1625 PCM Unexpected Reset
Circuit Description
The powertrain control module (PCM) monitors
unexpected PCM reset. This will not turn on MIL light on,
only record code DTC P1625.
Conditions for Setting the DTC
Clock or COP (Computer Operating Properly) reset.
Action Taken When the DTC Sets
The PCM will not illuminate the malfunction indicator
lamp (MIL).
The PCM will store conditions which were present
when the DTC was set as Failure Records only. This
information will not be stored as Freeze Frame data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL ªOFFº on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.
A history DTC P1625 will clear after 40 consecutive
warm-up cycles have occurred without a fault.
DTC P1625 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
P1625 stored alone does not need diagnosis. Clear
DTC code.
DTC P1625 ± PCM Unexpected Reset
StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition is ªONº.
2. Install the Tech 2.
3. Start the engine and let it Idle.
4. On the Tech 2, select ªDTC infoº.
Does the Tech 2 indicate DTC P1625 failed?
ÐGo to Step 3
Go to
Diagnostic
Aids
31. Ignition is ªONº.
2. Clear DTC P1625 by using the Tech 2 ªClear Infoº.
3. Start the engine and let it Idle.
4. On the Tech 2, select ªDTC infoº.
Does the Tech 2 indicate DTC P1625 failed?
ÐGo to Step 4
Go to
Diagnostic
Aids
41. Check for aftermarket electronics, such as
transceiver, stereos, and anti theft devices. They
may radiate EMI into the control system if they are
improperly installed. (This may cause a false sensor
reading and turn on the MIL.)
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairÐ
Page 1463 of 2100

6E±496
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1635 Reference Voltage # 1 Circuit Fault
D06RY00093
Circuit Description
The TP sensor # 1 shares a 5 Volt reference with the
PCM.
If the PCM detects the 5 Volt reference for the TP sensor #
1 is failure, DTCP1635 will be set.
Conditions for setting the DTC
The ignition is ªONº.
The 5 Volt reference voltage for the TP sensor # 1 is
less than 4 volts.
The 5 Volt reference voltage for the TP 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 conditions which were present
when the DTC was set as Failure Records only. This
information will not be stored as Freeze Frame data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL ªOFFº on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.
A history DTC P1635will clear after 40 consecutive trip
cycles during which the warm up cycles have occurred
without a fault.
DTC P1635 can be cleared using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed. Tech2 ª Clear Infoº function or by disconnecting
the PCM battery feed.
Page 1464 of 2100

6E±497
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1635 Reference Voltage # 1 Circuit Fault
StepActionValue(s)Ye sNo
1Was the ªOn-Board(OBD)System Checkº performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªONº, engine not running.
2. Using a DVM at the PCM side of the connector,
check the voltage at terminal S38 (RED) pin.
Is the voltage in specified range?
4.95 ± 5.0V
Go to ETC
System
Check
Go to Step 3
31. Ignition ªONº, engine not running.
2. Using a DVM at the PCM side of the connector,
check the voltage at terminal F20 (RED/WHT) pin.
Is the voltage in specified range?
11.6 ± 12.7VGo to Step 4 Go to Step 5
41. Ignition ªONº, engine not running.
2. Using a DVM at the PCM side of the connector,
check the voltage at terminal F57 (RED/WHT) pin.
Is the voltage in specified range?
11.6 ± 12.7VGo to Step 6 Go to Step 5
5Observe the battery voltage and circuit. If a problems
found, repair it as necessary.
Was the problem found?
ÐVerify repairGo to Step 6
6Replace the PCM.
IMPORTANT:
The replacement PCM must be programmed. Refer to
ON-Vehicle Service in Power Control Module and
Sensors for procedures.
And also refer to latest Service Bulletin. Check to see if
the latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ
Page 1465 of 2100

6E±498
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1639 Reference Voltage # 2 Circuit Fault
060R200064
Circuit Description
The AP sensor # 1shares 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 ªONº.
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 conditions which were present
when the DTC was set as Failure Records only. This
information will not be stored as Freeze Frame data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL ªOFFº 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
cycles during which the warm up cycles have occurred
without a fault.
DTC P1639 can be cleared using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed. Tech 2 ªClear Infoº function or by disconnecting
the PCM battery feed.
Page 1466 of 2100

6E±499
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1639 Reference Voltage # 2 Circuit Fault
StepActionValue(s)Ye sNo
1Was the ªOn-Board (OBD) System Checkº performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªONº, engine not running.
2. Using a DVM at the PCM side of the connector,
check the voltage at terminal S36 (BLK) pin.
Is the voltage in specified range?
4.95 ± 5.0V
Go to ETC
System
Check
Go to Step 3
31. Ignition ªONº, engine not running.
2. Using a DVM at the PCM side of the connector,
check the voltage at terminal F20(RED/WHT) pin.
Is the voltage in specified range?
11.6 ± 12.7VGo to Step 4 Go to Step 5
41. Ignition ªONº, engine not running.
2. Using a DVM at the PCM side of the connector,
check the voltage at terminal F57 (RED/WHT) pin.
Is the voltage in specified range?
11.6 ± 12.7VGo to Step 6 Go to Step 5
5Observe the battery voltage and circuit.
If a problem is found, repair it as necessary.
Was the problem found?
ÐVerify repairGo to Step 6
6Replace the PCM.
IMPORTANT:
The replacement PCM must be programmed. Refer to
ON-Vehicle Service in Power Control Module and
Sensors for procedures.
And also refer to latest Service Bulletin. Check to see if
the latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ
Page 1469 of 2100
6E±502
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P1640 ± Driver-1-Output Circuit Fault (ODM)
StepNo Ye s Value(s) Action
131. Connect the PCM.
2. Start the engine and let it idle.
3. Backprobe the affected terminal at the PCM with a
DVM.
Was the voltage equal to the specified value?
+BGo to Step 15Go to Step 14
141. Run the engine at idle.
2. Check for battery voltage at the fuse for the affected
circuit.
Was battery voltage available at the fuse?
ÐGo to Step 10Go to Step 9
15Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
On-Vehicle Service in
Powertrain Control Module and Sensors for
procedures.
And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ