Cummins ISB CM850 (2003-06) Fault Code: 436 PID: 105 SPN: 105 FMI: 2 Intake Manifold 1 Temperature – Data Erratic, Intermittent, or Incorrect. The intake manifold temperature sensor is reading an erratic value at initial key ON. The engine intake manifold temperature is compared to the engine coolant temperature and catalyst inlet temperature at initial key ON. The ECM must not see engine speed for a period of eight hours before this diagnostic will run. If the value of engine intake manifold temperature does not match the temperature readings from the engine coolant temperature and the catalyst inlet temperature within...

Cummins ISB CM850 (2003-06) Fault Code: 441 PID: SID 168 SPN: 168 FMI: 1 Battery 1 Voltage – Data Valid but Below Normal Operational Range – Moderately Severe Level. ECM supply voltage is below the minimum system voltage level. This fault code is logged when the ECM battery supply voltage drops below 6 volts. 1)Verify that the ECM unswitched power is coming from the batteries and not the starter or other device. Check for possible weak batteries.2)If the ECM unswitched battery supply is taken from the starter, check for low voltage during cranking. Low voltage during cranking can cause the...

Cummins ISB CM850 (2003-06) Fault Code: 442 PID: 168 SPN: 168 FMI: 0 Battery 1 Voltage – Data Valid but Above Normal Operational Range – Moderately Severe Level. ECM supply voltage is above the maximum system voltage level. This fault code is logged when the ECM battery supply voltage exceed 36 volts. C Possible causes : 1)Faulty alternator or regulator that is overcharging the system2)Batteries connected in series instead of parallel3)Incorrect jump-starting procedure. Possible repairs: 1)Install the battery system correctly.2)Repair or replace the alternator, regulator, and/or the OEM wiring to the alternator. Cummins ISB CM850 (2003-06) Fault Code: 441 PID:...

Cummins ISB CM850 (2003-06) Fault Code: 443 PID: SID 221 SPN: 1043 FMI: 4 Accelerator Pedal or Lever Position Sensor Supply Voltage Circuit – Voltage Below Normal or Shorted to Low Source. Low voltage detected at sensor supply circuit to the accelerator pedal or lever position sensor. Low voltage on the +5 VDC supply line can be caused by a short circuit to ground in the supply line, a short circuit between the supply line and return circuit, a failed accelerator, or a failed ECM power supply. Possible repairs: 1)Replace the accelerator pedal or lever position sensor.2)Repair or replace the...

Cummins ISB CM850 (2003-06) Fault Code: 449 (Auto) PID: 94 SPN: 157 FMI: 0 Injector Metering Rail Number 1 Pressure – Data Valid But Above Normal Operating Range – Most Severe Level. The ECM has detected that fuel pressure in the rail fuel is higher than the commanded pressure. Fault Code 449 is activated when the sensed rail fuel pressure reaches the opening pressure of the rail fuel pressure relief valve. Sensed pressure has exceeded system target range. An electric fuel control actuator with excessive leakage will result in high rail fuel pressures at idle or light load, and Fault...