PACCAR PX-9 CM2350 (2013-17) Fault Code:331 PID:SID 2 SPN:652 FMI:5 Injector Solenoid Driver Cylinder 2 Circuit – Current Below Normal or Open Circuit

Reason:
Injector Solenoid Driver Cylinder 2 Circuit – Current Below Normal or Open Circuit. Current detected at injector 2 when voltage is turned OFF.

Effect:
Possible reduced engine performance.

Circuit Description:
The injector solenoid valves control fueling quantity and injection timing. The engine control module (ECM) energizes the solenoid by closing a high-side and a low-side switch. Each injector circuit has a dedicated low side switch that completes the circuit path to ground inside the ECM.

Component Location:
The engine harness connects the ECM to the pass-through connector(s) that are located in the rocker housing. Internal injector harnesses are located under the valve cover and connect the injectors to the engine harness at the pass-through connector(s).

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected a circuit error on an injector(s) circuit. The ECM will disable the injection event for the affected injector(s) circuit if there is excessive current.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
2) The injector will be disabled for the malfunctioning cylinder.
3) Exhaust Gas Recirculation (EGR) valve operation will be disabled.
4) Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.

Conditions for Clearing the Fault Code:
1) To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
4) For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
5) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
If more than one injector fault code is occurring, and the faults occur for injector circuits in the same bank, a short circuit exists. If a fault condition is intermittent, and especially if more than one injector fault code is occurring, look for a wire harness that can short to components inside the rocker housing or a short circuit to ground in the injector solenoid. When looking for short circuits in the injector harnesses, pay particular attention to the wire insulation, making sure there are no shorts to a rocker lever.

An intermittent short can result if the wiring harness insulation rubs through near a rocker lever. An intermittent short can cause a single injector fault code. If the fault(s) occur intermittently, the engine can exhibit a misfire even if the injector circuit fault code does not always register. If a single cylinder exhibits misfires, look for an open circuit problem. If several cylinders on the same bank exhibit misfires, look for a short circuit anywhere in the bank of cylinders.

Possible causes of a single injector fault include:
1) Open circuit in the engine harness(es) or injector solenoid
2) High resistance in a single injector or injector solenoid
3) Extremely low resistance in an injector solenoid (injector shorted internally but not to ground)
4) Malfunctioning or damaged ECM.

Possible causes of multiple injector fault codes in the same bank of injectors include:
1) Short circuit in the engine harness(es) – either shorts to ground or to other wires in the engine harness
2) Short circuit in any of the three injectors in the bank – shorts to ground Malfunctioning or damaged ECM

Same Bank Fault Codes:
1) Bank 1 – Front Bank: Fault Codes 322, 324, 331
2) Bank 2 – Rear Bank: Fault Codes 323, 325, 332