Paccar

PACCAR MX (2004 Emissions) Fault Code: P104C Inlet Air Pressure in Inlet Manifold – Data Valid but Too Low

SET CONDITIONS:
The PCI ECU (D420) detects that the measured boost pressure is more than 0.5 bar [7.3 psi] lower than the expected boost pressure for more than 50 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. when the engine is running at a steady load, and
2. when the coolant temperature is above 50°C [122°F], and
3. when ambient temperature is between -15 and 40°C [5 and 104°F], and;
4. The engine mode is SCR high efficiency or standard.

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:
1. Leaking inlet air system
2. Boost pressure sensor deviation
3. Humidity sensor deviation
4. Turbocharger failure

ADDITIONAL INFORMATION:
1. The measured boost pressure is compared with an expected boost pressure.
2. The boost pressure is measured by the boost pressure sensor (F802).

PACCAR MX (2004 Emissions) Fault Code: P104D Exhaust Gas Pressure Before Turbine – Data Valid but Too High

SET CONDITIONS:
The PCI ECU (D420) detects that the measured pressure before turbine is higher than the expected pressure before turbine for more than 50 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. When the engine speed is between 1000 and 1700 rpm and
2. When the engine is running at a steady load and
3. When the coolant temperature is above 50°C [122°F] and
4. The engine mode is SCR high efficiency or standard or protection.

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:
1. Clogged EGR system
2. Blocked exhaust system
3. Restricted pressure sensor before turbine tube
4. Pressure sensor before turbine deviation
5. Air leakage between intercooler and inlet manifold

ADDITIONAL INFORMATION:
1. The measured pressure before turbine is compared with an expected pressure before turbine.
2. The pressure before turbine is measured by the pressure sensor before turbine (F826).

PACCAR MX (2004 Emissions) Fault Code: P104E Exhaust Gas Pressure Before Turbine – Data Valid but Too Low, During Engine Braking

SET CONDITIONS:
The PCI ECU (D420) detects that the expected exhaust gas pressure before turbine cannot be reached while the VTG turbocharger is at its minimum position.

DIAGNOSTIC CONDITION:
This diagnostic runs when the engine mode is engine brake.

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. The end-stops of the VTG turbocharger actuator not programmed correctly.

IMPORTANT: In an attempt the solve VTG turbocharger actuator position related DTCs, turbocharger actuators are occasionally recalibrated by a technician. By doing so, the actuator is mistakenly calibrated to a smaller span than the initial maximum span of the turbocharger mechanism. In that case, the requested pressure before turbine cannot be reached during engine braking, resulting in DTC P104E.

2. Leaking exhaust system
3. Leaking pressure sensor before turbine tube
4. Pressure sensor before turbine deviation

ADDITIONAL INFORMATION:
1. The VTG turbocharger is used to create back pressure during engine braking.
2. The VTG turbocharger control depends, among other factors, on the exhaust gas pressure before turbine.
3. The VTG turbocharger is controlled by the VTG turbocharger actuator (L037).
4. The exhaust gas pressure before turbine is measured by the pressure sensor before turbine (F826).

PACCAR MX (2004 Emissions) Fault Code: P1050 Exhaust Gas Pressure After BPV – Data Erratic, Intermittent or Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that measured pressure after BPV differs too much from the expected pressure after BPV for more than 50 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. Engine speed is between 1000 and 1700 rpm and
2. Engine is running at a steady load and
3. Coolant temperature is above 50?C [122?F] and
4. The engine mode is SCR high efficiency or standard

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:
1. Leakage in the exhaust system between engine and DPF filter inlet
2. Blockage in the exhaust system between engine and DPF filter inlet
3. Pressure sensor after BPV deviation
4. DPF pressure sensor deviation

ADDITIONAL INFORMATION:
1. The measured pressure after BPV is compared with an expected pressure after BPV. For the calculation of the expected value, the DPF pressure sensor (F837) and ambient pressure are used, among others.

2. The pressure after BPV is measured by the pressure sensor after BPV (F823).

PACCAR MX (2004 Emissions) Fault Code: P1051 Grid Heater – Data Erratic, Intermittent, or Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that the boost temperature has risen less than 40?C [104?F] within 20 seconds after activating the glow installation.

DIAGNOSTIC CONDITION:
This diagnostic runs once after the ignition is keyed on and when the glow installation is activated.

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. Faulty glow installation wiring
2. Faulty grid heater relay
3. Faulty glow element

ADDITIONAL INFORMATION:
1. For this diagnostic, the boost temperature is measured at the moment the glow installation (pre and post) is activated and again after 20 seconds. When the glow installation works correctly, the boost temperature is higher after 20 seconds.

2. The PCI activates the glow element (B341) by energizing the grid heater relay (G014).

3. The boost temperature is measured by the boost temperature sensor (F804).

PACCAR MX (2004 Emissions) Fault Code: P1053 Speed Functions Off Switch – Data Erratic, Intermittent, or Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that both the variable speed limiter activation and deactivation switches are active at the same time.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the ignition is 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:
Mechanical failure or damage to the variable speed limiter switches

ADDITIONAL INFORMATION:
The variable speed limiter allows the vehicle speed to be limited to a speed set by the driver.

PACCAR MX (2004 Emissions) Fault Code: P1055 Retarder Switches – Data Erratic, Intermittent, or Incorrect

SET CONDITIONS:
The PCI ECU (D420) receives a CAN message with an invalid position of the retarder switch.

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

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

POSSIBLE CAUSES:
Mechanical failure or damage to the retarder switch

ADDITIONAL INFORMATION:
The retarder is a wear-resistant continuous brake. It is primarily intended for use in prolonged braking, for example when decelerating from high speed on a level road or when driving downhill.

PACCAR MX (2004 Emissions) Fault Code: P1057 Exhaust Gas Pressure Before Turbine – Data Valid but Too Low

SET CONDITIONS:
The PCI ECU (D420) detects that measured pressure before turbine is lower than the expected pressure before turbine for more than 50 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. Engine speed is between 1000 and 1700 rpm and
2. Engine is running at a steady load and
3. Coolant temperature is above 50?C [122?F] and
4. the engine mode is SCR high efficiency or standard or protection

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:
1. Leaking exhaust system
2. Leaking pressure sensor before turbine tube
3. Pressure sensor before turbine deviation

ADDITIONAL INFORMATION:
1. The measured pressure before turbine is compared with an expected pressure before turbine.
2. The pressure before turbine is measured by the pressure sensor before turbine (F826).