When Monitored:
With the engine running in closed loop mode, the ambient/battery temperature above (-7°C) 20°F, altitude
below 8500 ft.
Set Condition:
If the PCM multiplies short term compensation by long term adaptive as wellas a purge fuel multiplier and the
result is below a certain value for 30 seconds over two trips, a freeze frameis stored, the MIL illuminates and
a trouble code is stored. Two Trip Fault. Three good trips to turn off the MIL.
Possible Causes
EXHAUST LEAK
ENGINE MECHANICAL
1/2O2SENSOR
(K141) O2 SENSOR 1/2 SIGNAL CIRCUIT
(K299) O2 1/2 HEATER CONTROL CIRCUIT
(K904) O2 RETURN DOWNSTREAM CIRCUIT
FUEL CONTAMINATION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Check the vehicle repair history. If the 1/2 O2 has been replaced makesure that the O2 sensor was
properly installed and meets OEM specification.
NOTE: Check for contaminants that may have damaged the O2 Sensor: contaminated fuel, unapproved sil-
icone, oil and coolant.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.EXHAUST LEAK
Turn the ignition off.
WARNING: To avoid personal injury from the exhaust system being hot, allowthe exhaust to cool down to
a safe temperature before performing a physical inspection. Failure to follow these instructions can result in
personal injury or death.
Visually and Physically inspect the exhaust system for holes, cracks and blockage in the exhaust system.
Is the exhaust system is good condition?
Ye s>>
Go To 3
No>>
Repair or Replace as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
With the engine running in closed loop mode, the ambient/battery temperature above (-7°C) 20°F, altitude
below 8500 ft.
Set Condition:
If the PCM multiplies short term compensation by long term adaptive as wellas a purge fuel multiplier and the
result is below a certain value for 30 seconds over two trips, a freeze frameis stored, the MIL illuminates and
a trouble code is stored. Two Trip Fault. Three good trips to turn off the MIL.
Possible Causes
EXHAUST LEAK
ENGINE MECHANICAL
1/2O2SENSOR
(K141) O2 SENSOR 1/2 SIGNAL CIRCUIT
(K299) O2 HEATER 1/2 CONTROL CIRCUIT
(K904) O2 RETURN DOWNSTREAM CIRCUIT
FUEL CONTAMINATION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Check the vehicle repair history. If the 1/2 O2 has been replaced makesure that the O2 sensor was
properly installed and meets OEM specification.
NOTE: Check for contaminants that may have damaged the O2 Sensor: contaminated fuel, unapproved sil-
icone, oil and coolant.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.EXHAUST LEAK
Turn the ignition off.
WARNING: To avoid personal injury from the exhaust system being hot, allowthe exhaust to cool down to
a safe temperature before performing a physical inspection. Failure to follow these instructions can result in
personal injury or death.
Visually and Physically inspect the exhaust system for holes, cracks and blockage in the exhaust system.
Is the exhaust system is good condition?
Ye s>>
Go To 3
No>>
Repair or Replace as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
With the engine running in closed loop mode, the ambient/battery temperature above (-7°C) 20°F, altitude
below 8500 ft and fuel level greater than 15%.
Set Condition:
If the PCM multiplies short term compensation by long term adaptive and a certain percentage is exceeded for
two trips, a freeze frame is stored, the MIL illuminates and a trouble code is stored. Two Trip Fault. Three good
trips to turn off the MIL.
Possible Causes
EXHAUST LEAK
ENGINE MECHANICAL
2/2O2SENSOR
(K243) O2 2/2 SIGNAL CIRCUIT
(K399) O2 HEATER 2/2 CONTROL CIRCUIT
(K904) O2 RETURN DOWNSTREAM CIRCUIT
FUEL CONTAMINATION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Check the vehicle repair history. If the 2/2 O2 has been replaced makesure that the O2 sensor was
properly installed and meets OEM specification.
NOTE: Check for contaminants that may have damaged the O2 Sensor: contaminated fuel, unapproved sil-
icone, oil and coolant.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.EXHAUST LEAK
Turn the ignition off.
WARNING: To avoid personal injury from the exhaust system being hot, allowthe exhaust to cool down to
a safe temperature before performing a physical inspection. Failure to follow these instructions can result in
personal injury or death.
Visually and Physically inspect the exhaust system for holes, cracks and blockage in the exhaust system.
Is the exhaust system is good condition?
Ye s>>
Go To 3
No>>
Repair or Replace as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
With the engine running in closed loop mode, the ambient/battery temperature above (-7°C) 20°F, altitude
below 8500 ft.
Set Condition:
If the PCM multiplies short term compensation by long term adaptive as wellas a purge fuel multiplier and the
result is below a certain value for 30 seconds over two trips, a freeze frameis stored, the MIL illuminates and
a trouble code is stored. Two Trip Fault. Three good trips to turn off the MIL.
Possible Causes
EXHAUST LEAK
ENGINE MECHANICAL
2/2O2SENSOR
(K342) O2 SENSOR 2/2 SIGNAL CIRCUIT
(K399) O2 SENSOR 2/2 HEATER CONTROL CIRCUIT
(K904) O2 RETURN DOWNSTREAM CIRCUIT
FUEL CONTAMINATION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Check the vehicle repair history. If the 2/2 O2 has been replaced makesure that the O2 sensor was
properly installed and meets OEM specification.
NOTE: Check for contaminants that may have damaged the O2 Sensor: contaminated fuel, unapproved sil-
icone, oil and coolant.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.EXHAUST LEAK
Turn the ignition off.
WARNING: To avoid personal injury from the exhaust system being hot, allowthe exhaust to cool down to
a safe temperature before performing a physical inspection. Failure to follow these instructions can result in
personal injury or death.
Visually and Physically inspect the exhaust system for holes, cracks and blockage in the exhaust system.
Is the exhaust system is good condition?
Ye s>>
Go To 3
No>>
Repair or Replace as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
Ignition on.
Set Condition:
PCM recognizes Vehicle speed input No.2 erratic or high. VSS No.2 is based on the average of the Front
Wheel Speeds. One trip fault and the code will set within 5 seconds. No MIL and No ETC light. Cruise is
disabled.
Possible Causes
(B222) VEHICLE SPEED NO.2 SIGNAL CIRCUIT SHORTED TO VOLTAGE
(B222) VEHICLE SPEED NO.2 SIGNAL CIRCUIT OPEN
(B222) VEHICLE SPEED NO.2 SIGNAL CIRCUIT SHORTED TO GROUND
TIRE CIRCUMFERENCE
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
NOTE: Check for any Bus Communication DTCs. If no Bus or Communication DTCsare set, check for active
DTCs stored in the Anti-Lock Brake Module. Any bus or communication DTCs orVSS DTCs in the Anti-Lock
Brake Module must be properly diagnosed before continuing.
With a scan tool, read DTCs.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.VISUAL INSPECTION
NOTE: This code can set due to tire circumference differences and from the front or rear wheels being on
a slippery surface while the opposite tires are not.
This code may also set on a hard acceleration on loose gravel or during otheroff road driving conditions.
Check tire pressure of all the tires.
Checktirewearonallthetires.
Ask the customer what the road and driving conditions were like when the fault set.
Were any problems found?
Ye s>>
Repair as necessary. If the code set during a front OR rear wheel spin condition, no repair is necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
When Monitored:
Ignition on, Engine running, and no ECT DTCs present.
Set Condition:
PCM recognizes that the ECT has failed its self coherence test. The coolanttemp should only change at a
certain rate, if this rate is too slow or too fast this fault will set. Two trip fault. Three good trips to clear MIL.
ETC light will illuminate on first trip failure.
Possible Causes
LOW COOLANT LEVEL
(K2) ECT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(K2) ECT SIGNAL CIRCUIT OPEN
(K900) SENSOR GROUND CIRCUIT OPEN
(K2) ECT SIGNAL CIRCUIT SHORTED TO GROUND
(K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND
THERMOSTAT
ECT SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
NOTE: If this code sets during extreme ambient temperatures, improper installation of a block heater could
be the cause of this DTC.
With a scan tool, read DTCs.
Diagnose all other ECT and Cooling System codes before continuing.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.LOW COOLANT LEVEL
NOTE: If a Engine Coolant Temperature (ECT) DTC is set along with this code,diagnose the ECT DTC first.
NOTE: Inspect the ECT terminals and related PCM terminals. Ensure the terminals are free from corrosion
and damage.
NOTE: The best way to diagnose this DTC is to allow the vehicle to sit overnight outside in order to have
a totally cold soaked engine.
NOTE: Extremely cold outside ambient temperatures may have caused this DTCtoset.
NOTE: Need to make sure that no Cooling System DTCs are set or changes that would make the warm up
much slower or much faster: broken water pump can set this, addition of aftermarket auxiliary cooler can
set this DTC.
WARNING: Never open the cooling system when the engine is hot. The system isunder pressure. Failure to
follow these instructions can result in personal injury or death. Allow the engine to cool before opening the
cooling system.
P2610-PCM INTERNAL SHUTDOWN TIMER FAST RATIONALITY
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Ignition on and battery voltage greater than 10 volts.
Set Condition:
Internal PCM failure detected. One Trip Fault. Three good trips to turn offthe MIL.
Possible Causes
PCM FUSED IGNITION SWITCH CIRCUIT
PCM INTERNAL
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.PCM IGNITION CIRCUITS
Turn the ignition off.
Disconnect the C1 PCM harness connector.
CAUTION: Do not probe the PCM harness connectors. Probing the
PCM harness connectors will damage the PCM terminals resulting
in poor terminal to pin connection. Install Miller Special Tool #8815
to perform diagnosis.
With a 12-volt test light connected to ground and with special tool
#8815 installed, probe the (F202), (F1), and (T751) Fused Ignition
Switch circuits.
Perform the above check with the Ignition key in the off lock position,
Ignition on, engine not running position, and during cranking.
Wiggle the related wire harness while probing the special tool with the
test light to try to interrupt the circuit.
Does the test light illuminate brightly?
Ye s>>
Go To 2
No>>
Repair the open or excessive resistance in the (F202), (F1), and (T751) Fused Ignition Switch (Off, Run,
Start) circuits. Inspect the related fuse, if the fuse is open check the circuits for a short to ground.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.PCM
The Powertrain Control Module is reporting internal errors.
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
P3400-MDS RATIONALITY BANK 1
For a complete wiring diagramRefer to Section 8W.
Theory of Operation
When all criteria has been met, power is supplied to each MDS Solenoid when the engine is making a transition
from 8 cylinder mode to 4 cylinder mode. By actuating the solenoid, oil pressure is raised to the pair of lifters that
coincide with each particular solenoid. The oil pressure pushes in the locking pins that allows the lifter to collapse,
decoupling the valves and camshaft.
When Monitored:
Transition from 8 to 4 cylinder mode.
Set Condition:
O2 sensor readings on Bank 1 side indicate a lean condition while in 4 cylinder mode. One trip fault.
Possible Causes
INSUFFICIENT OIL PRESSURE ACTING ON THE LIFTER LOCKING PINS
OIL PASSAGES RESTRICTED
LIFTER
MDS SOLENOID
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read DTCs.
NOTE: Diagnose any Oil Pressure DTCs before continuing.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.MDS SOLENOID 1
Turn the ignition off.
Remove the Intake Manifold per Service Information.
Turn the ignition on.
With the scan tool actuate the MDS Solenoid 1.
Can you feel and hear the Solenoid Actuating?
Ye s>>
Go To 3
No>>
Remove the Solenoid and check for any debris that may be blocking the oil passages to the Solenoid.
If the passages are clogged, clean the passages and replace the MDS Solenoid1.Ifthepassagesare
not clogged with debris, replace the MDS Solenoid 1.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)