Paccar

PACCAR MX (2004 Emissions) Fault Code: P0473 Exhaust Gas Pressure Before Turbine – Voltage Too High or Short Circuit to Supply on ECU (D420) Pin (C83)

SET CONDITIONS:
This DTC is set when the ECU detects a higher voltage than expected on the signal or control circuit of the ECU.

DIAGNOSTIC CONDITION:
The diagnostic runs continuously when the ignition is keyed on.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
The DTC changes to inactive after the diagnostic runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. The sensor or actuator signal wiring has a short circuit to supply.
2. A malfunction of the sensor or actuator

PACCAR MX (2004 Emissions) Fault Code: P047C Exhaust Gas Pressure After BPV – Voltage Too Low or Short Circuit to Ground on ECU (D420) Pin (C81)

SET CONDITIONS:
This DTC is set when the ECU detects a lower voltage than expected on the signal or control circuit of the ECU.

DIAGNOSTIC CONDITION:
The diagnostic runs continuously when the ignition is keyed on.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
The DTC changes to inactive after the diagnostic runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. The sensor or actuator signal wiring is interrupted.
2. The sensor or actuator signal wiring has a short circuit to ground.
3. A malfunction in the power supply of the sensor or actuator.
4. A malfunction of the sensor or actuator.

ADDITIONAL INFORMATION:
Multiple sensor related voltage-too-low DTCs can indicate a malfunction within a 5-V sensor power supply circuit of the PCI ECU.

PACCAR MX (2004 Emissions) Fault Code: P047D Exhaust Gas Pressure After BPV – Voltage Too High or Short Circuit to Supply on ECU (D420) Pin (C81)

SET CONDITIONS:
This DTC is set when the ECU detects a higher voltage than expected on the signal or control circuit of the ECU.

DIAGNOSTIC CONDITION:
The diagnostic runs continuously when the ignition is keyed on.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
The DTC changes to inactive after the diagnostic runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. The sensor or actuator signal wiring has a short circuit to supply.
2. A malfunction of the sensor or actuator.

PACCAR MX (2004 Emissions) Fault Code: P0480 Electronically Controlled Fan – Current Too Low or Open Circuit on ECU (D420) Pin (C74)

SET CONDITIONS:
The PCI ECU (D420) detects a too low current on the control circuit of the electronically controlled fan clutch (B335) for more than 25 seconds.

DIAGNOSTIC CONDITION:
The diagnostic runs continuously when the ignition is keyed on.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
The DTC changes to inactive 45 minutes after the diagnostic runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
Open circuit in the control circuit of the electronically controlled fan clutch (B335) caused by:
1. Wiring issues between ECU (D420) and the electronically controlled fan clutch (B335).
2. Malfunction in the electronically controlled fan clutch (B335).

PACCAR MX (2004 Emissions) Fault Code: P0486 EGR Pressure Difference – Data Erratic, Intermittent, or Incorrect at Ignition On

SET CONDITIONS:
The PCI ECU (D420) detects that measured EGR pressure difference deviates by more than 5 mbar [0.07 psi].

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the ignition is on (engine not running).

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
EGR pressure difference sensor deviation

ADDITIONAL INFORMATION:
The EGR pressure difference sensor (F751) is monitored against ambient pressure.

PACCAR MX (2004 Emissions) Fault Code: P0493 Fan Speed Control – Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that the actual fan speed is higher than expected.

DIAGNOSTIC CONDITION:
This diagnostic runs every 300 seconds:
1. When the engine has been running for more than 300 seconds
2. When the engine speed is greater than 1000 rpm
3. When the coolant temperature is above 70°C [158°F]

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
Faulty electronically controlled fan clutch

ADDITIONAL INFORMATION:
1. The negative side coil of the electronically controlled fan clutch (B335) is controlled with the duty cycle by the PCI ECU. When the duty cycle is:
– High, the fan speed is low or decreasing
– Low, the fan speed is high or increasing
2. The fan speed is monitored by the fan clutch internal speed sensor.

PACCAR MX (2004 Emissions) Fault Code: P0501 Vehicle Speed Sensor – Data Erratic, Intermittent, or Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that the measured vehicle speed is unlikely.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. When engine speed is above 900 rpm and
2. The engine speed changes more than 300 rpm in a period of more than 90 seconds and
3. Engine torque changes in a period of more than 90 seconds

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
Faulty vehicle speed signal

ADDITIONAL INFORMATION:
The PCI ECU uses information from the accelerator pedal position, engine speed, and engine torque to determine if the vehicle is in motion.

PACCAR MX (2004 Emissions) Fault Code: P0502 Vehicle Speed Sensor – Voltage Too Low or Short Circuit to Ground on ECU (D420) Pin (B40)

SET CONDITIONS:
This DTC is set when the ECU detects a lower voltage than expected on the signal or control circuit of the ECU.

DIAGNOSTIC CONDITION:
The diagnostic runs continuously when the ignition is keyed on.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
The DTC changes to inactive after the diagnostic runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. The sensor or actuator signal wiring is interrupted.
2. The sensor or actuator signal wiring has a short circuit to ground.
3. A malfunction in the power supply of the sensor or actuator
4. A malfunction of the sensor or actuator

ADDITIONAL INFORMATION:
Multiple sensor related voltage-too-low DTCs can indicate a malfunction within a 5-V sensor power supply circuit of the PCI ECU.

PACCAR MX (2004 Emissions) Fault Code: P0503 Vehicle Speed Sensor – Out of Range

SET CONDITIONS:
The PCI ECU (D420) detects that the measured vehicle speed is higher than 140 km/h [87 mph].

DIAGNOSTIC CONDITION:
This diagnostic runs continuously after ignition is keyed on.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. Driving at high speed (e.g., downhill)
2. Faulty vehicle speed signal

ADDITIONAL INFORMATION:
1. The PCI ECU uses the vehicle speed sensor as an input for the vehicle speed.
2. When this DTC is detected five times during one drive cycle, it stays active. A drive cycle is the period between ignition on and off with the diagnostic condition met. After 4 hours of continuous ignition on or engine operation, a new drive cycle is started.