Encountering a check engine light in your 2005 Jeep can be concerning. Modern vehicles like the 2005 Jeep Wrangler and Grand Cherokee utilize an On-Board Diagnostics system, specifically OBD2, to monitor various systems and pinpoint potential issues. When something goes wrong, the system generates diagnostic trouble codes (DTCs), commonly known as OBD2 codes, which illuminate the check engine light. Understanding these codes is the first step towards diagnosing and resolving the problem, keeping your Jeep running smoothly.
This guide provides a comprehensive list of OBD2 codes relevant to your 2005 Jeep. While the original source provided codes for various Jeep models and engine types, we will focus on the codes most pertinent to 2005 models and later, ensuring you have the most accurate information for your vehicle.
Understanding OBD2 Codes for your 2005 Jeep
For 2005 Jeep models, you’ll primarily be concerned with OBD2 codes for fuel-injected engines from 1996 and later. These codes are standardized across manufacturers and provide a consistent way to diagnose issues. They are typically alphanumeric, starting with a letter indicating the system affected:
- P (Powertrain): Engine, transmission, and related components. This is the most common category for check engine lights.
- B (Body): Body control systems like power windows, locks, and airbags.
- C (Chassis): Chassis systems such as ABS (Anti-lock Braking System) and suspension.
- U (Network): Communication network issues between vehicle modules.
The number following the letter provides further information about the specific fault. Here’s a detailed breakdown of common OBD2 codes you might encounter in your 2005 Jeep:
OBD2 Codes for 1996 and Later Jeep Models (Including 2005)
These codes are often displayed by OBD2 scanners and are crucial for diagnosing issues in your 2005 Jeep.
P0107 – Manifold Absolute Pressure/Barometric Pressure Circuit Low Input
This code indicates that the Manifold Absolute Pressure (MAP) sensor is reporting lower than expected voltage. This sensor measures air pressure in the intake manifold, and a low reading could indicate a vacuum leak, a faulty sensor, or wiring issues.
P0108 – Manifold Absolute Pressure/Barometric Pressure Circuit High Input
Conversely, this code means the MAP sensor is reporting higher than expected voltage. This could be due to a short circuit in the sensor wiring, a faulty sensor, or issues with the ECU (Engine Control Unit).
P0112 – Intake Air Temperature Circuit Low Input
The Intake Air Temperature (IAT) sensor measures the temperature of the air entering the engine. A low input reading suggests a short circuit, a faulty sensor, or wiring problems.
P0113 – Intake Air Temperature Circuit High Input
A high input reading from the IAT sensor indicates a potential open circuit, a faulty sensor, or wiring issues.
P0117 – Engine Coolant Temperature Circuit Low Input
This code signifies that the Engine Coolant Temperature (ECT) sensor is reporting a lower than expected temperature. This could be due to a short circuit, a faulty sensor, or low coolant levels.
P0118 – Engine Coolant Temperature Circuit High Input
A high input reading from the ECT sensor suggests an open circuit, a faulty sensor, or wiring problems.
P0121 – Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem
This code indicates an issue with the Throttle Position Sensor (TPS), which monitors the throttle valve’s position. A range/performance problem means the sensor’s signal is inconsistent with the expected range, potentially due to a faulty sensor or mechanical issues with the throttle body.
P0122 – Throttle/Pedal Position Sensor/Switch A Circuit Low Input
A low input from the TPS suggests a short circuit, a faulty sensor, or wiring problems.
P0123 – Throttle/Pedal Position Sensor/Switch A Circuit High Input
A high input reading from the TPS indicates an open circuit, a faulty sensor, or wiring issues.
P0125 – Insufficient Coolant Temperature for Closed Loop Fuel Control
This code indicates that the engine coolant has not reached the required temperature for the engine control system to enter closed loop operation. This could be caused by a faulty thermostat or issues with the cooling system.
P0129 – Catalyst Monitor Slow O2 Sensor (Bank 1 Sensor 2)
This code points to a slow response from the downstream oxygen sensor (Sensor 2) on Bank 1 (the side of the engine with cylinder #1). This sensor monitors the efficiency of the catalytic converter.
P0131 – Left Bank and Upstream O2 Sensor Voltage Shorted to Ground
Indicates a low voltage signal from the upstream oxygen sensor (Sensor 1) on Bank 1, possibly due to a short circuit to ground.
P0132 – Left Upstream O2 Sensor Shorted to Voltage
Indicates a high voltage signal from the upstream oxygen sensor (Sensor 1) on Bank 1, possibly due to a short circuit to voltage.
P0133 – Upstream O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)
This code indicates a slow response from the upstream oxygen sensor (Sensor 1) on Bank 1, meaning it’s not switching between rich and lean conditions as quickly as expected.
P0135 – O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
This code points to a problem with the heater circuit of the upstream oxygen sensor (Sensor 1) on Bank 1. The heater helps the sensor reach operating temperature quickly for accurate readings.
P0137 – Left Bank Downstream or Downstream and Pre-Catalyst O2 Sensor Voltage Shorted to Ground
Indicates a low voltage signal from the downstream oxygen sensor (Sensor 2) on Bank 1, possibly due to a short circuit to ground.
P0138 – Left Bank Downstream or Downstream and Pre-Catalyst O2 Sensor Shorted to Voltage
Indicates a high voltage signal from the downstream oxygen sensor (Sensor 2) on Bank 1, possibly due to a short circuit to voltage.
P0141 – Downstream, Left Bank Downstream or Pre-Catalyst O2 Sensor Heater Failure
This code points to a malfunction in the heater circuit of the downstream oxygen sensor (Sensor 2) on Bank 1.
P0152 – Left Upstream O2 Sensor Slow Response
Similar to P0133, but potentially referring to a different bank or sensor if applicable to the specific Jeep model.
P0162 – Charging System Voltage Too Low
This code indicates that the vehicle’s charging system voltage is lower than expected, which could be due to a faulty alternator, battery, or related wiring.
P0171 – Right Rear (or just) Fuel System Too Lean
This code indicates that the engine’s air-fuel mixture is too lean (too much air, not enough fuel) on Bank 1. This could be caused by vacuum leaks, fuel delivery issues, or a faulty oxygen sensor.
P0172 – Left Bank or Fuel System Too Rich
This code indicates that the engine’s air-fuel mixture is too rich (too much fuel, not enough air) on Bank 2. Potential causes include faulty injectors, a faulty oxygen sensor, or a malfunctioning fuel pressure regulator.
P0201 – Injector No. 1 Control Circuit
P0202 – Injector No. 2 Control Circuit
P0203 – Injector No. 3 Control Circuit
P0204 – Injector No. 4 Control Circuit
P0205 – Injector No. 5 Control Circuit
P0206 – Injector No. 6 Control Circuit
P0207 – Injector No. 7 Control Circuit
P0208 – Injector No. 8 Control Circuit
These codes (P0201 through P0208) indicate a problem with the control circuit for specific fuel injectors (numbered 1 through 8). This could involve wiring issues, faulty injectors, or problems with the ECU’s injector drivers.
P0300 – Random/Multiple Cylinder Misfire Detected
This code indicates that the engine is experiencing misfires in multiple cylinders or randomly across cylinders. Misfires can be caused by ignition problems (spark plugs, wires, coils), fuel delivery issues, vacuum leaks, or compression problems.
P0301 – Cylinder No. 1 – Misfire Detected
P0302 – Cylinder No. 2 – Misfire Detected
P0303 – Cylinder No. 3 – Misfire Detected
P0304 – Cylinder No. 4 – Misfire Detected
P0305 – Cylinder No. 5 – Misfire Detected
P0306 – Cylinder No. 6 – Misfire Detected
P0307 – Cylinder No. 7 – Misfire Detected
P0308 – Cylinder No. 8 – Misfire Detected
These codes (P0301 through P0308) pinpoint misfires to specific cylinders (numbered 1 through 8). This helps narrow down the source of the misfire.
P0320 – No Crank Reference Signal PCM
This code indicates that the Powertrain Control Module (PCM) is not receiving a crank reference signal, which is essential for ignition and fuel timing. This could be due to a faulty crankshaft position sensor, wiring issues, or PCM problems.
P0340 – No Cam Signal at PCM
This code means the PCM is not receiving a signal from the camshaft position sensor. This sensor is crucial for proper engine timing and fuel injection. A faulty sensor or wiring issue is likely the cause.
P0351 – Ignition Coil No. 1 Primary Circuit
This code suggests a problem with the primary circuit of ignition coil number 1. This could be due to a faulty coil, wiring problems, or issues with the ECU’s coil driver.
P0420 – Left Bank Catalytic Converter or Just Catalytic Converter Efficiency Failure
This code indicates that the catalytic converter’s efficiency is below the required threshold. This could be due to a failing catalytic converter, exhaust leaks, or engine problems causing excessive emissions.
P0441 – Evaporative Purge Flow Monitor Failure
This code points to a problem with the evaporative emission (EVAP) purge flow monitor system, which controls fuel vapor recirculation.
P0442 – Evaporative Emission Control System Leak Detected (Small Leak)
This code indicates a small leak in the EVAP system. Common causes include a loose or faulty gas cap, cracked hoses, or a malfunctioning purge valve.
P0443 – Evap Purge Solenoid Circuit
This code points to a problem with the EVAP purge solenoid circuit, which controls the flow of fuel vapors into the intake manifold.
P0455 – Evaporative Emission Control System Leak Detected (Gross Leak)
This code indicates a large leak in the EVAP system, often caused by a missing or severely damaged gas cap, or large cracks in EVAP system components.
P0460 – Fuel Level Unit No Change Over Miles
This code indicates that the fuel level sensor reading has not changed over a certain distance driven, which could be due to a faulty fuel level sensor or a wiring issue.
P0462 – Fuel Level Sending Unit Voltage Too Low
This code suggests a low voltage signal from the fuel level sending unit, potentially due to a short circuit, a faulty sensor, or wiring problems.
P0463 – Fuel Level Sending Unit Voltage Too High
A high voltage signal from the fuel level sending unit indicates an open circuit, a faulty sensor, or wiring issues.
P0500 – No Vehicle Speed Sensor Signal
This code means the vehicle speed sensor (VSS) is not sending a signal to the ECU. This can affect speedometer operation, transmission shifting, and cruise control.
P0505 – Idle Air Control Motor Circuits
This code indicates a problem with the Idle Air Control (IAC) motor circuits, which regulate engine idle speed.
P0600 – PCM/Serial Communication Link Malfunction
This code suggests a malfunction in the communication link between the PCM and other vehicle modules.
P0601 – Internal Controller Failure
This code indicates an internal fault within the PCM itself.
P0622 – Generator Field Not Switching Properly
This code points to a problem with the generator (alternator) field switching circuit, which controls the alternator’s output.
P0645 – A/C Clutch Relay Circuit
This code indicates a problem with the air conditioning (A/C) clutch relay circuit.
P0711 – Transmission Fluid Temperature Sensor, No Temperature Rise After Start
This code suggests that the Transmission Fluid Temperature (TFT) sensor is not detecting a temperature increase after the vehicle has been started.
P0712 – Transmission Fluid Temperature Sensor Voltage Too Low
Indicates a low voltage signal from the TFT sensor, potentially due to a short circuit, faulty sensor, or wiring issues.
P0713 – Transmission Fluid Temperature Sensor Voltage Too High
A high voltage signal from the TFT sensor suggests an open circuit, faulty sensor, or wiring problems.
P0720 – Low Output Speed Sensor RPM Above 15 MPH
This code indicates that the output speed sensor is reporting a low RPM even when the vehicle speed is above 15 MPH, suggesting a sensor malfunction.
P0740 – Torque Converter Clutch, No RPM Drop at Lockup
This code indicates that the torque converter clutch is not locking up properly, which can affect fuel economy and transmission performance.
P0743 – Torque Converter Clutch Solenoid/Trans Relay Circuits
This code points to a problem with the torque converter clutch solenoid or transmission relay circuits.
P0748 – Governor Pressure Solenoid Control/Trans Relay Circuits
This code indicates a problem with the governor pressure solenoid control or transmission relay circuits, often related to automatic transmission pressure regulation.
P0751 – Overdrive Switch Pressed (LO) More Than 5 Minutes
This code might be specific to certain Jeep models and indicates that the overdrive switch has been in the low (LO) position for an extended period.
P0753 – Trans 3-4 Shift Solenoid/Trans Relay Circuits
This code points to a problem with the 3-4 shift solenoid or transmission relay circuits in the automatic transmission.
P0783 – 3-4 Shift Solenoid, No RPM Drop @ 3-4 Shift
This code indicates that there is no RPM drop during the 3-4 shift, suggesting a problem with the 3-4 shift solenoid or related transmission components.
P1195 – Catalyst Monitor Slow O2 Sensor (Bank 1 Sensor 1)
Similar to P0133, indicating a slow response from the upstream oxygen sensor (Sensor 1) on Bank 1.
P1197 – Catalyst Monitor Slow O2 Sensor (Bank 1 Sensor 2)
Similar to P0129, indicating a slow response from the downstream oxygen sensor (Sensor 2) on Bank 1.
P1281 – Engine is Cold Too Long
This code suggests that the engine is taking too long to reach its normal operating temperature, possibly due to a faulty thermostat.
P1282 – Fuel Pump Relay Control Circuit
This code points to a problem with the fuel pump relay control circuit.
P1294 – Target Idle Not Reached
This code indicates that the engine idle speed is not reaching the desired target RPM.
P1296 – No 5 Volts to MAP Sensor
This code means that the MAP sensor is not receiving the necessary 5-volt reference voltage, which is likely due to wiring issues or a PCM problem.
P1297 – No Change in MAP from Start to Run
This code indicates that the MAP sensor reading is not changing between engine start and run conditions, suggesting a sensor malfunction or vacuum leak.
P1388 – Auto Shutdown Relay Control Circuit
This code points to a problem with the Auto Shutdown (ASD) relay control circuit, which is crucial for engine operation.
P1389 – No ASD Relay Output Voltage at PCM
This code indicates that there is no output voltage from the ASD relay at the PCM, suggesting a problem with the relay or its circuit.
P1391 – Intermittent Loss of CMP or CKP
This code indicates an intermittent loss of signal from either the Camshaft Position (CMP) sensor or the Crankshaft Position (CKP) sensor.
P1398 – Misfire Adaptive Numerator at Limit or No Crank Sensor Learn
This code is related to misfire detection and/or the crankshaft position sensor learning process.
P1486 – EVAP Leak Monitor Pinched Hose or Obstruction Found
This code indicates that the EVAP leak monitor system has detected a pinched hose or obstruction in the EVAP system.
P1492 – Battery Temp Sensor Voltage Too High
This code suggests a high voltage reading from the battery temperature sensor, potentially due to an open circuit, faulty sensor, or wiring issues.
P1493 – Battery Temp Sensor Voltage Too Low
A low voltage reading from the battery temperature sensor indicates a short circuit, faulty sensor, or wiring problems.
P1494 – Leak Detection Pump Pressure Switch or Mechanical Fault
This code points to a problem with the leak detection pump pressure switch or a mechanical fault within the EVAP leak detection pump system.
P1495 – Leak Detection Pump Solenoid Circuit
This code indicates a problem with the leak detection pump solenoid circuit.
P1594 – Charging System Voltage Too High
This code indicates that the charging system voltage is higher than expected, which could be due to a faulty voltage regulator or alternator.
P1595 – Speed Control Solenoid Circuits
This code points to a problem with the speed control solenoid circuits, related to the cruise control system.
P1596 – Speed Control Switch Always High
This code suggests that the speed control switch is always reporting a high signal, potentially due to a faulty switch or wiring issue.
P1597 – Speed Control Switch Always Low
Conversely, this code indicates that the speed control switch is always reporting a low signal.
P1683 – Speed Control Power Circuit
This code points to a problem with the power circuit for the speed control system.
P1696 – PCM Failure EEPROM Write Denied
P1698 – PCM Failure EEPROM Write Denied
These codes (P1696 and P1698) both indicate a failure within the PCM related to writing to the EEPROM (Electrically Erasable Programmable Read-Only Memory). This often suggests a PCM malfunction.
P1756 – Governor Pressure Not Equal to Target @ 15-20 PSI
This code, specific to automatic transmissions, indicates that the governor pressure is not within the expected range at a certain pressure level.
P1757 – Governor Pressure Above 3 PSI in Gear with 0 MPH
This transmission-related code indicates that the governor pressure is too high when the vehicle is in gear and not moving.
P1762 – Governor Pressure Sensor Offset Volts Too Low or High
This code points to an issue with the governor pressure sensor’s offset voltage, indicating a sensor malfunction.
P1763 – Governor Pressure Sensor Volts Too High
Indicates a high voltage reading from the governor pressure sensor.
P1764 – Governor Pressure Sensor Volts Too Low
Indicates a low voltage reading from the governor pressure sensor.
P1765 – Trans 12 Volts Supply Relay Control Circuit
This code points to a problem with the 12-volt supply relay control circuit for the transmission.
P1899 – P/N Switch Stuck in Park or in Gear
This code indicates that the Park/Neutral (P/N) switch is stuck in either the Park or Gear position, potentially affecting starting or transmission operation.
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Conclusion
This comprehensive list of 2005 Jeep Obd2 Codes provides a valuable starting point for diagnosing check engine light issues. When you encounter a code, use this guide to understand the potential problem area. Remember, while OBD2 codes offer valuable clues, they are not a definitive diagnosis. Further investigation, including visual inspections, sensor testing, and potentially professional mechanic consultation, is often necessary to pinpoint the root cause and ensure proper repair. By understanding these codes, you can be better informed and proactive in maintaining your 2005 Jeep and keeping it running reliably for years to come.
