Understanding Bosch Diesel Electronic Fuel Injection High-Pressure Common Rail System Fault Codes

The Bosch Diesel Electronic Fuel Injection (EFI) High-Pressure Common Rail (CR) system is an essential component in modern diesel engines, ensuring optimal fuel delivery and engine performance. As with all mechanical systems, the fuel injectors in these systems will eventually wear out, and some faults may arise during use. While most of these issues are minor, error codes related to the system can be confusing for those unfamiliar with the technology. Without a solid understanding of the Bosch EFI High-Pressure Common Rail system, even small problems can lead to unnecessary downtime.

In this blog, we will explore the common fault codes found in Bosch diesel systems.

• 0 Exhaust brake valve feedback does not match ECU control command
• P0016 Phase sensor and crankshaft sensor relative position deviation
• P0045 Turbocharger actuator control line open circuit
• P0046 Turbocharger actuator control line ECU internal driver module overheating
• P0047 Turbocharger actuator control line short circuit to ground
• P0048 Turbocharger actuator control line short circuit to high voltage
• P0069 Boost pressure sensor drift
• P0071 Invalid environmental temperature sensor signal from CAN
• P0072 Ambient temperature sensor output voltage below the lower limit (wire shorted to ground)
• P0073 Ambient temperature sensor output voltage above the upper limit (wire open or shorted to high voltage)
• P0087 Fuel pressure below the minimum limit
• P0088 Fuel pressure above the maximum limit
• P0097 Intake air temperature sensor voltage too low (wire shorted to ground)
• P0098 Intake air temperature sensor voltage too high (wire open or shorted to high voltage)
• P0100 The uncorrected air mass flow signal measured by the airflow meter is too high or too low (wire open or shorted)
• P0101 The corrected air mass flow signal measured by the airflow meter is too high or too low
• P0102 Negative drift of the air mass flow meter
• P0103 Positive drift of the air mass flow meter
• P0104 Zero-point drift of the air mass flow meter
• P0110 Additional air temperature sensor on the air mass flow meter has a wiring short circuit or open circuit
• P0112 Additional air temperature sensor on the air mass flow meter detects a temperature that is too low
• P0113 Additional air temperature sensor on the air mass flow meter detects a temperature that is too high
• P0115 Invalid coolant temperature signal received via CAN
• P0116 Unreliable dynamic characteristics of the coolant temperature sensor
• P0117 Coolant temperature sensor output voltage below the lower limit (wire shorted to ground)
• P0118 Coolant temperature sensor output voltage above the upper limit (wire open or shorted to high voltage)
• P0122 Throttle pedal potentiometer 1 output voltage below the lower limit
• P0123 Throttle pedal potentiometer 1 output voltage above the upper limit
• P0128 Unreliable static characteristics of the coolant temperature sensor
• P0182 Fuel temperature sensor output voltage too low (wire shorted to ground)
• P0183 Fuel temperature sensor output voltage too high (wire open or shorted to high voltage)
• P0191 Excessive positive drift of the rail pressure sensor
• P0192 Rail pressure sensor output voltage below the lower limit (wire shorted to ground)
• P0193 Rail pressure sensor output voltage above the upper limit (wire open or shorted to high voltage)
• P0194 Excessive negative drift of the rail pressure sensor
• P0195 Invalid oil temperature signal received via CAN
• P0197 Oil temperature sensor output voltage below the lower limit
• P0198 Oil temperature sensor output voltage above the upper limit
• P0201 Cylinder 1 injector open circuit
• P0202 Cylinder 2 injector open circuit
• P0203 Cylinder 3 injector open circuit
• P0204 Cylinder 4 injector open circuit
• P0205 Cylinder 5 injector open circuit
• P0206 Cylinder 6 injector open circuit
• P0222 Throttle pedal potentiometer 2 output voltage below the lower limit
• P0223 Throttle pedal potentiometer 2 output voltage above the upper limit
• P0234 Actual boost pressure significantly exceeds the control target
• P0235 Invalid boost pressure signal received via CAN
• P0237 Boost pressure sensor output voltage below the lower limit (wire shorted to ground)
• P0238 Boost pressure sensor output voltage above the upper limit (wire open or shorted to high voltage)
• P0251 Fuel metering unit control line open circuit
• P0252 Fuel metering unit ECU internal driver circuit overheating
• P0253 Fuel metering unit control line shorted to ground
• P0254 Fuel metering unit control line shorted to high voltage
• P025C Not in use
• P025D Not in use
• P0261 Cylinder 1 injector low-end shorted to high-end
• P0262 Cylinder 1 injector low-end shorted to high voltage
• P0263 Cylinder 1 injector other errors
• P0264 Cylinder 2 injector low-end shorted to high-end
• P0265 Cylinder 2 injector low-end shorted to high voltage
• P0266 Cylinder 2 injector other errors
• P0267 Cylinder 3 injector low-end shorted to high-end
• P0268 Cylinder 3 injector low-end shorted to high voltage
• P0269 Cylinder 3 injector other errors
• P0270 Cylinder 4 injector low-end shorted to high-end
• P0271 Cylinder 4 injector low-end shorted to high voltage
• P0272 Cylinder 4 injector other errors
• P0273 Cylinder 5 injector low-end shorted to high-end
• P0274 Cylinder 5 injector low-end shorted to high voltage
• P0275 Cylinder 5 injector other errors
• P0276 Cylinder 6 injector low-end shorted to high-end
• P0277 Cylinder 6 injector low-end shorted to high voltage
• P0278 Cylinder 6 injector other errors
• P0299 Actual boost pressure significantly lower than the control target
• P0300 Multiple cylinder misfire
• P0301 Cylinder 1 misfire
• P0302 Cylinder 2 misfire
• P0303 Cylinder 3 misfire
• P0304 Cylinder 4 misfire
• P0305 Cylinder 5 misfire
• P0306 Cylinder 6 misfire
• P0335 No crankshaft sensor signal
• P0336 Incorrect crankshaft sensor signal
• P0340 No camshaft sensor signal
• P0341 Incorrect camshaft sensor signal
• P0380 ECU does not request glow plug operation, but the glow plug is active
• P0382 ECU requests glow plug operation, but the glow plug is not active
• P0383 ECU control line to the glow plug is shorted to ground
• P0384 ECU control line to the glow plug is shorted to high voltage
• P0401 Actual fresh air intake exceeds the target intake set by the EGR system
• P0402 Actual fresh air intake is less than the target intake set by the EGR system
• P0403 EGR valve actuator control line ECU internal driver module overheating
• P0404 EGR valve actuator control line open circuit
• P0405 EGR valve position sensor voltage below the lower limit (wire shorted to ground)
• P0406 EGR valve position sensor voltage above the upper limit (wire open or shorted to high voltage)
• P0475 Exhaust brake valve control line open circuit
• P0476 Exhaust brake valve ECU internal driver module
• P0477 Exhaust brake valve control line shorted to ground
• P0478 Exhaust brake valve control line shorted to high voltage
• P0480 ECU control line to fan 1 open circuit
• P0481 ECU control line to fan 2 open circuit
• P0483 ECU internal driver module for fan 1 control line overheating
• P0484 ECU internal driver module for fan 2 control line overheating
• P0487 Throttle actuator control line open circuit
• P0488 Throttle actuator ECU internal driver module overheating
• P0489 EGR valve actuator control line shorted to ground
• P0490 EGR valve actuator control line shorted to high voltage
• P0500 Vehicle speed sensor hardware error
• P0501 Vehicle speed sensor signal unreliable
• P0503 Vehicle speed sensor exceeds maximum value
• P0504 Main and secondary brake pedal signal comparison is unreliable
• P0513 Mismatch between sent and received anti-theft signals
• P0520 Engine oil pressure signal from CAN is invalid
• P0521 Engine oil pressure is too high and unreliable
• P0522 Engine oil pressure sensor output voltage is below the lower limit (wire shorted to ground)
• P0523 Engine oil pressure sensor output voltage is above the upper limit (wire open or shorted to high voltage)
• P0524 Engine oil pressure is too low and unreliable
• P0530 ECU internal receiving circuit failure for duty-cycle-based air conditioning pressure signal
• P0531 Duty-cycle-based air conditioning pressure signal exceeds the upper or lower limit or enters a special fault mode
• P0532 Duty cycle of the air conditioning pressure signal is below the lower limit
• P0533 Duty cycle of the air conditioning pressure signal exceeds the upper limit
• P0562 Battery voltage is too low
• P0563 Battery voltage is too high
• P0571 Brake pedal signal transmitted via CAN is unreliable
• P0575 Cruise control request is unreliable
• P0607 ECU internal control chip error
• P060A Communication failure in ECU internal CJ940 chip
• P060B ECU internal analog-to-digital conversion module fault
• P060C ECU internal watchdog chip error
• P0611 Injection count is restricted
• P0615 ECU starter motor control wire open circuit or driver module overheating
• P0616 ECU starter motor control wire shorted to ground
• P0617 ECU starter motor control wire shorted to high voltage
• P0627 Fuel pre-supply pump control wire open circuit
• P0628 Fuel pre-supply pump control wire shorted to ground
• P0629 Fuel pre-supply pump control wire shorted to high voltage
• P062A ECU internal output module for fuel pre-supply pump overheating
• P062B Injector driver chip fault
• P062F ECU internal EEPROM read/write error
• P0638 Throttle valve feedback signal does not match ECU control request
• P0642 Sensor power supply voltage 1 too low
• P0643 Sensor power supply voltage 1 too high
• P0645 ECU air conditioning control wire open circuit or ECU internal driver module overheating
• P0646 ECU air conditioning control wire shorted to ground
• P0647 ECU air conditioning control wire shorted to high voltage
• P0650 ECU OBD fault indicator output wire fault (short circuit, open circuit)
• P0652 Sensor power supply voltage 2 too low
• P0653 Sensor power supply voltage 2 too high
• P0660 Variable swirl ratio actuator control wire open circuit
• P0661 Variable swirl ratio actuator control wire shorted to ground
• P0662 Variable swirl ratio actuator control wire shorted to high voltage
• P0670 ECU control wire for glow plug open circuit or its driver module overheating
• P0686 Main relay opens too early
• P0687 Main relay opens too late
• P0691 ECU control wire for fan 1 shorted to ground
• P0692 ECU control wire for fan 1 shorted to high voltage
• P0693 ECU control wire for fan 2 shorted to ground
• P0694 ECU control wire for fan 2 shorted to high voltage
• P0698 Sensor power supply voltage 3 too low
• P0699 Sensor power supply voltage 3 too high
• P0704 Clutch signal not reliable
• P0856 Not in use
• P1007 Not in use
• P100D Oil temperature and coolant temperature comparison not reliable
• P1011 Rail pressure controller positive deviation exceeds upper limit
• P1012 Rail pressure controller positive deviation severely exceeds upper limit
• P1013 Rail pressure controller negative deviation lower than lower limit
• P1014 Fuel pressure value not reliable during engine overrun
• P1100 Air mass flow meter software correction too large
• P1101 Air mass flow meter additional air temperature sensor’s analog output voltage too high or too low
• P1102 Air mass flow meter additional air temperature sensor’s duty cycle output signal too high or too low
• P1103 Coolant temperature and oil temperature sensor signal comparison not reliable
• P1106 Air mass flow meter additional air temperature sensor’s duty cycle output signal period too high
• P1107 Air mass flow meter additional air temperature sensor’s duty cycle output signal period too low
• P1109 Not in use
• P110A Not in use
• P110B Not in use
• P110C Not in use
• P1112 Coolant temperature relative to air mass flow meter’s temperature sensor reliability check error
• P1200 Injector 1 positive correction value too high
• P1201 Injector 1 negative correction value too high
• P1202 Injector 2 positive correction value too high
• P1203 Injector 2 negative correction value too high
• P1204 Injector 3 positive correction value too high
• P1205 Injector 3 negative correction value too high
• P1206 Injector 4 positive correction value too high
• P1207 Injector 4 negative correction value too high
• P1208 Injector 5 positive correction value too high
• P1209 Injector 5 negative correction value too high
• P120A Injector 6 positive correction value too high
• P120B Injector 6 negative correction value too high
• P120C Injector 1 dynamic positive correction value too high
• P120D Injector 1 dynamic negative correction value too high
• P120E Injector 2 dynamic positive correction value too high
• P120F Injector 2 dynamic negative correction value too high
• P1210 Injector 3 dynamic positive correction value too high
• P1211 Injector 3 dynamic negative correction value too high
• P1212 Injector 4 dynamic positive correction value too high
• P1213 Injector 4 dynamic negative correction value too high
• P1214 Injector 5 dynamic positive correction value too high
• P1215 Injector 5 dynamic negative correction value too high
• P1216 Injector 6 dynamic positive correction value too high
• P1217 Injector 6 dynamic negative correction value too high
• P1223 Injector high-end short circuit
• P1224 Injector low-end short circuit to ground
• P1225 Injector other error
• P1226 Injector other error
• P1227 Injector other error
• P1228 Injector other error
• P1229 Injector open circuit
• P122A Injector other error
• P122B Injector high-end short circuit (not in use, only for 6-cylinder engines)
• P122C Injector low-end short circuit to ground (not in use, only for 6-cylinder engines)
• P122D Injector other error (not in use, only for 6-cylinder engines)
• P122E Injector other error (not in use, only for 6-cylinder engines)
• P122F Injector other error (not in use, only for 6-cylinder engines)
• P1230 Injector other error (not in use, only for 6-cylinder engines)
• P1231 Injector open circuit (not in use, only for 6-cylinder engines)
• P1232 Injector other error (not in use, only for 6-cylinder engines)
• P1233 Injector other error for cylinder 1
• P1234 Injector other error for cylinder 1
• P1235 Injector other error for cylinder 1
• P1236 Injector other error for cylinder 2
• P1237 Injector other error for cylinder 2
• P1238 Injector other error for cylinder 2
• P1239 Injector other error for cylinder 3
• P123A Injector other error for cylinder 3
• P123B Injector other error for cylinder 3
• P123C Injector other error for cylinder 4
• P123D Injector other error for cylinder 4
• P123E Injector other error for cylinder 4
• P123F Injector other error for cylinder 5
• P1240 Injector other error for cylinder 5
• P1241 Injector other error for cylinder 5
• P1242 Injector other error for cylinder 6
• P1243 Injector other error for cylinder 6
• P1244 Injector other error for cylinder 6
• P12FF Not in use
• P1301 Not in use
• P1562 Airflow meter supply voltage too high or too low
• P1601 ECU to dashboard coolant temperature output line shorted to high level
• P1602 ECU to dashboard coolant temperature output line shorted to ground
• P1603 ECU to dashboard coolant temperature output line open circuit
• P1604 ECU to dashboard coolant temperature output internal driver module overheat
• P1605 ECU to dashboard engine speed output line shorted to high level
• P1606 ECU to dashboard engine speed output line shorted to ground
• P1607 ECU to dashboard engine speed output line open circuit
• P1608 ECU to dashboard preheating light output line shorted to high level
• P1609 ECU to dashboard preheating light output line shorted to ground
• P160A ECU to dashboard preheating light output line open circuit
• P160B ECU to dashboard preheating light output line driver module overheat
• P160C ECU internal analog-to-digital conversion module failure
• P1613 Anti-runaway monitor detected excessive power-on time
• P1614 Anti-runaway monitor detected unreliable engine speed
• P1615 Not in use
• P1616 Watchdog error cannot shut down
• P1617 Internal supply voltage too high error cannot shut down
• P1618 Internal supply voltage too low error cannot shut down
• P1619 ECU to system fault light output line shorted to high level
• P161A ECU to system fault light output line shorted to ground
• P161B ECU to system fault light output line open circuit
• P161C ECU to system fault light driver module overheat
• P161D Vehicle model data corrupted
• P161E Vehicle model data cannot be selected
• P161F Not in use
• P1620 Variable swirl ratio actuator driver module overheat
• P1621 ECU to dashboard fuel consumption rate signal output line shorted to high level
• P1622 ECU to dashboard fuel consumption rate signal output line shorted to ground
• P1623 ECU to dashboard fuel consumption rate signal output line open circuit
• P1624 ECU to dashboard fuel consumption rate signal output driver module overheat
• P1625 ECU to exhaust brake display light output line shorted to high level
• P1626 ECU to exhaust brake display light output line shorted to ground
• P1627 ECU to exhaust brake display light output line open circuit
• P1628 ECU to exhaust brake display light output driver module overheat
• P1629 Throttle position sensor error
• P1630 Software reset
• P1631 Not in use
• P1637 ECU internal power module voltage too high
• P1638 ECU internal power module voltage too low
• P1641 Not in use
• P2135 Throttle pedal potentiometer 1 and potentiometer 2 comparison not credible
• P2141 Throttle actuator control line shorted to ground
• P2142 Throttle actuator control line shorted to high level
• P2157 Vehicle speed signal from CAN transmission invalid
• P2226 Atmospheric pressure sensor signal from CAN transmission invalid
• P2228 Atmospheric pressure sensor output voltage too low
• P2229 Atmospheric pressure sensor output voltage too high
• P2264 Diesel fuel filter water separator water level sensor fault
• P2267 Diesel fuel filter water separator water level full
• P2299 Both throttle and brake pedals depressed simultaneously
• P245A EGR cooler bypass valve actuator control line open
• P245B EGR cooler bypass valve actuator control line driver module overheat
• P245C EGR cooler bypass valve actuator control line shorted to ground
• P245D EGR cooler bypass valve actuator control line shorted to high level
• P2517 Analog air conditioning pressure sensor voltage signal below lower limit (short to low level)
• P2518 Analog air conditioning pressure sensor voltage signal above upper limit (shorted or short to high level)
• P2519 Air conditioning switch signal from CAN transmission invalid
• P2530 Shutdown button stuck
• P2533 Ignition switch error
• U0404 TSC request not credible

Troubleshooting Bosch Diesel EFI High-Pressure Common Rail System Faults

Step 1: Check for Wiring and Connector Issues

Electrical faults are common causes of many injector-related error codes. Begin by inspecting the wiring harnesses and connectors associated with the fuel injectors. Look for signs of wear, corrosion, or loose connections.

Step 2: Reset the ECU

If communication errors are detected, resetting the ECU may help clear temporary faults. Always ensure the vehicle’s battery is disconnected before attempting any ECU reset.

Step 3: Replace Faulty Injectors

If fault codes indicate a persistent problem with one or more injectors, replacement may be necessary. Over time, injectors can become clogged or damaged, leading to poor fuel delivery and engine performance.

Step 4: Perform a Comprehensive Diagnostic

If the issue persists, performing a thorough diagnostic using specialized tools can help identify the root cause. This may involve checking sensor readings, actuator responses, and fuel pressure to ensure all components are functioning correctly.

Conclusion

Understanding and diagnosing fault codes in the Bosch Diesel Electronic Fuel Injection High-Pressure Common Rail system is essential for maintaining optimal engine performance. By familiarizing yourself with common error codes and knowing how to troubleshoot them, you can minimize downtime and reduce repair costs. Always follow manufacturer guidelines and consult a professional mechanic if you’re unsure how to proceed with repairs or diagnostics.

By staying informed and proactive, you ensure that your diesel engine runs smoothly and efficiently for years to come.