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Fiat / FCA
🔴 High
Fiat / FCA
P0038
FIAT P0038 HO2S Heater Control Circuit High (Bank 1 Sensor 2)
The P0038 fault on your Fiat / FCA indicates a FIAT P0038 HO2S Heater Control Circuit High (Bank 1 Sensor 2). Excessive voltage detected in the circuit, which usually points to a short-to-power or a failing component with excessive internal resistance.
Brand
Fiat / FCA
Fault Code
P0038
Severity
🔴 High
Models
500, Punto, Bravo, Alfa 147/156/159, Doblo, Ducato
🛠️ Diagnostic Overview
Difficulty Level
🛠️🛠️🛠️
Hard (Advanced)
Estimated Time
⏱️ 3-6 Hours
🧰 Required Tools
- ✓ Digital Multimeter
- ✓ Socket Wrench & Hand Tools
- ✓ Smoke Leak Detector / Vacuum Gauge
- ✓ Electrical Contact Cleaner Spray
⚠️ Possible Causes
- • Vacuum leaks in the intake system
- • Dirty sensor elements (oil/carbon)
- • Frayed wires due to engine vibration.
🔧 Recommended Fixes
- → Trace the circuit wiring from the sensor to the ECU. Secure all connections and ensure the battery is providing a stable 12V output.
🔴 This is a high-priority fault. Have the vehicle inspected by a qualified technician as soon as possible.
🚗 Commonly Affected Vehicles
🏭 Fiat / FCA – Other Common Fault Codes
U0100
FIAT U0100 Lost Communication With ECM/PCM A
🚨 Critical
B1000
FIAT B1000 Airbag Control Module Fault
🟡 Medium
P2293
FIAT P2293 Fuel Pressure Regulator 2 Performance
🔴 High
P2279
FIAT P2279 Intake Air System Leak
🟡 Medium
P219A
FIAT P219A Bank 1 Air-Fuel Ratio Imbalance
🟡 Medium
P2181
FIAT P2181 Cooling System Performance
🟡 Medium
P2096
FIAT P2096 Post Catalyst Fuel Trim System Too Lean
🟡 Medium
P2015
FIAT P2015 Intake Manifold Runner Position Sensor Circuit Range
🔴 High
P1101
FIAT P1101 MAF Sensor Out of Self Test Range
🟡 Medium
P0741
FIAT P0741 Torque Converter Clutch Circuit Performance
🟡 Medium
P0700
FIAT P0700 Transmission Control System Malfunction
🚨 Critical
P0600
FIAT P0600 Serial Communication Link Malfunction
🟡 Medium
P0507
FIAT P0507 Idle Control System RPM Higher Than Expected
🟡 Medium
P0500
FIAT P0500 Vehicle Speed Sensor Malfunction
🟡 Medium
P0456
FIAT P0456 EVAP System Leak Detected (very small leak)
🟡 Medium
P0455
FIAT P0455 EVAP System Leak Detected (large leak)
🟡 Medium
P0442
FIAT P0442 EVAP System Leak Detected (small leak)
🟡 Medium
P0441
FIAT P0441 Evaporative Emission System Incorrect Purge Flow
🟡 Medium
P0430
FIAT P0430 Catalyst System Efficiency Below Threshold Bank 2
🟡 Medium
P0420
FIAT P0420 Catalyst System Efficiency Below Threshold
🟡 Medium
P0401
FIAT P0401 Exhaust Gas Recirculation Flow Insufficient
🟡 Medium
P0400
FIAT P0400 Exhaust Gas Recirculation Flow Malfunction
🟡 Medium
P0335
FIAT P0335 Crankshaft Position Sensor A Circuit Malfunction
🔴 High
P0325
FIAT P0325 Knock Sensor 1 Circuit Malfunction
🟡 Medium
P0304
FIAT P0304 Cylinder 4 Misfire Detected
🟡 Medium
P0303
FIAT P0303 Cylinder 3 Misfire Detected
🟡 Medium
P0302
FIAT P0302 Cylinder 2 Misfire Detected
🟡 Medium
P0301
FIAT P0301 Cylinder 1 Misfire Detected
🔴 High
P0300
FIAT P0300 Random/Multiple Cylinder Misfire Detected
🚨 Critical
P0234
FIAT P0234 Turbocharger Overboost Condition
🚨 Critical
P0175
FIAT P0175 System Too Rich Bank 2
🟡 Medium
P0174
FIAT P0174 System Too Lean Bank 2
🔴 High
P0172
FIAT P0172 System Too Rich Bank 1
🟡 Medium
P0171
FIAT P0171 System Too Lean Bank 1
🔴 High
P0141
FIAT P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
🟡 Medium
P0135
FIAT P0135 O2 Sensor Heater Circuit Malfunction
🟡 Medium
P0133
FIAT P0133 O2 Sensor Circuit Slow Response
🟡 Medium
P0130
FIAT P0130 O2 Sensor Circuit Malfunction
🔴 High
P0128
FIAT P0128 Coolant Thermostat Malfunction
🟡 Medium
P0113
FIAT P0113 Intake Air Temperature Circuit High Input
🟡 Medium
P0102
FIAT P0102 Mass Air Flow Circuit Low Input
🟡 Medium
P0101
FIAT P0101 Mass Air Flow Sensor Circuit Range/Performance
🟡 Medium
P0088
FIAT P0088 Fuel Rail/System Pressure - Too High
🟡 Medium
P0016
FIAT P0016 Crankshaft Position - Camshaft Position Correlation
🚨 Critical
P0012
FIAT P0012 A Camshaft Position Timing Over-Retarded
🟡 Medium
P0011
FIAT P0011 A Camshaft Position Timing Over-Advanced
🟡 Medium
P0010
FIAT P0010 A Camshaft Position Actuator Circuit
🟡 Medium
P0340
Camshaft Position Sensor Circuit Fault (MultiJet)
🔴 High
P0380
Glow Plug Circuit Malfunction (1.3 JTD Multijet)
🟡 Medium
P0191
Fuel Pressure Sensor Range/Performance (MultiJet)
🔴 High
P1610
ECU Immobiliser / BSI Communication Error
🔴 High
P0403
EGR Valve Circuit Malfunction (1.9 JTD)
🟡 Medium
P0299
Turbocharger Underboost (1.4 T-Jet / MultiAir)
🔴 High
P0087
Fuel Rail Pressure Too Low (Common Rail Diesel)
🔴 High
P0101
FIAT FIAT MAF Sensor Range/Performance
🟡 Medium
P0404
FIAT FIAT EGR System Performance Malfunction
🔴 High
P0236
FIAT FIAT Turbo Boost Sensor Circuit Range
🔴 High
P0683
FIAT FIAT Glow Plug Module Communication Fault
🟢 Low
P0520
FIAT FIAT Oil Pressure Sensor Circuit
🟡 Medium
P1325
FIAT FIAT Knock Sensor Circuit Performance
🔴 High
P0130
FIAT FIAT O2 Sensor Circuit (Bank 1 Sensor 1)
🟡 Medium
P0300
FIAT FIAT Random or Multiple Cylinder Misfire
🚨 Critical
P0480
FIAT FIAT Cooling Fan 1 Control Circuit Fault
🟡 Medium
P0091
FIAT FIAT Fuel Pressure Regulator Control
🚨 Critical
P0380
FIAT P0380 Glow Plug/Heater Circuit A Malfunction
🔴 High
P0403
FIAT P0403 EGR Control Circuit Malfunction
🔴 High
P0236
FIAT P0236 Turbocharger Boost Sensor Circuit Range
🔴 High
P0101
FIAT P0101 MAF Sensor Range/Performance
🔴 High
P0741
FIAT P0741 TCC Solenoid Performance
🔴 High
P1121
FIAT P1121 TPS Signal Inconsistent with MAF
🔴 High
P0480
FIAT P0480 Cooling Fan 1 Control Circuit
🔴 High
P0520
FIAT P0520 Oil Pressure Sensor Circuit
🔴 High
P0683
FIAT P0683 Glow Plug Module Comm Fault
🔴 High
P0130
FIAT P0130 O2 Sensor Circuit Bank 1
🔴 High
P0032
FIAT P0032 HO2S Heater Control Circuit High (Bank 1 Sensor 1)
🟢 Low
P0037
FIAT P0037 HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
🟢 Low
P0051
FIAT P0051 HO2S Heater Control Circuit Low (Bank 2 Sensor 1)
🟡 Medium
P0057
FIAT P0057 HO2S Heater Control Circuit Low (Bank 2 Sensor 2)
🟢 Low
P0058
FIAT P0058 HO2S Heater Control Circuit High (Bank 2 Sensor 2)
🔴 High
P0103
FIAT P0103 Mass or Volume Air Flow Circuit High Input
🟢 Low
P0107
FIAT P0107 Manifold Absolute Pressure/Barometric Pressure Circuit Low Input
🔴 High
P0108
FIAT P0108 Manifold Absolute Pressure/Barometric Pressure Circuit High Input
🟡 Medium
P0112
FIAT P0112 Intake Air Temperature Circuit Low Input
🟡 Medium
P0117
FIAT P0117 Engine Coolant Temperature Circuit Low Input
🚨 Critical
P0118
FIAT P0118 Engine Coolant Temperature Circuit High Input
🚨 Critical
P0122
FIAT P0122 Throttle/Pedal Position Sensor/Switch A Circuit Low Input
🟡 Medium
P0123
FIAT P0123 Throttle/Pedal Position Sensor/Switch A Circuit High Input
🟢 Low
P0125
FIAT P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control
🟢 Low
P0131
FIAT P0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
🔴 High
P0132
FIAT P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
🟡 Medium
P0134
FIAT P0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
🟡 Medium
P0137
FIAT P0137 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)
🟢 Low
P0138
FIAT P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
🚨 Critical
P0151
FIAT P0151 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)
🟢 Low
P0152
FIAT P0152 O2 Sensor Circuit High Voltage (Bank 2 Sensor 1)
🚨 Critical
P0157
FIAT P0157 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 2)
🟡 Medium
P0158
FIAT P0158 O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)
🔴 High
P0200
FIAT P0200 Injector Circuit Malfunction
🟡 Medium
P0231
FIAT P0231 Fuel Pump Secondary Circuit Low
🟡 Medium
P0232
FIAT P0232 Fuel Pump Secondary Circuit High
🟢 Low
P0327
FIAT P0327 Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)
🟢 Low
P0328
FIAT P0328 Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
🚨 Critical
P0332
FIAT P0332 Knock Sensor 2 Circuit Low Input (Bank 2)
🟡 Medium
P0333
FIAT P0333 Knock Sensor 2 Circuit High Input (Bank 2)
🔴 High
P0440
FIAT P0440 Evaporative Emission Control System Malfunction
🟡 Medium
P0443
FIAT P0443 Evaporative Emission System Purge Control Valve Circuit
🚨 Critical
P0446
FIAT P0446 Evaporative Emission System Vent Control Circuit Malfunction
🟢 Low
P0451
FIAT P0451 Evaporative Emission System Pressure Sensor Range/Performance
🔴 High
P0452
FIAT P0452 Evaporative Emission System Pressure Sensor Low Input
🟡 Medium
P0453
FIAT P0453 Evaporative Emission System Pressure Sensor High Input
🟢 Low
P0462
FIAT P0462 Fuel Level Sensor Circuit Low Input
🔴 High
P0463
FIAT P0463 Fuel Level Sensor Circuit High Input
🟢 Low
P0502
FIAT P0502 Vehicle Speed Sensor Circuit Low Input
🟢 Low
P0503
FIAT P0503 Vehicle Speed Sensor Intermittent/Erratic/High
🔴 High
P0505
FIAT P0505 Idle Control System Malfunction
🔴 High
P0506
FIAT P0506 Idle Control System RPM Lower Than Expected
🟡 Medium
P0562
FIAT P0562 System Voltage Low
🟢 Low
P0563
FIAT P0563 System Voltage High
🟡 Medium
P0601
FIAT P0601 Internal Control Module Memory Check Sum Error
🚨 Critical