Comprehensive diagnostic guide for OBD-II code P1119

Important Notes

• P1119 is a P1xxx code, which means it is a manufacturer-specific powertrain diagnostic trouble code. Generic (P0xxx) codes are defined across all makes, but P1xxx meanings vary by OEM and model. The exact meaning for P1119 depends on the vehicle application and the OEM's definitions (service manual or OEM diagnostic database). This guide presents a structured diagnostic approach for P1119 that works across many vehicles, with notes on a specific open-source mapping that lists P1119 as as one possible interpretation. Refer to the vehicle's OEM service information to confirm the exact P1119 definition for your model.
  • General concept of DTCs: DTCs are generated by the on-board diagnostics system when a parameter falls outside expected limits or a sensor/actuator is not behaving correctly. This is the foundational idea described in the OBD-II overview (Diagnostic Trouble Codes) from Wikipedia.
  • Powertrain codes context: P1xxx family codes are specifically powertrain-related and are commonly related to sensors, circuits, or control modules affecting engine performance and emissions.
  • Emissions/testing context: P1xxx codes are typically observed during emissions-related monitoring and testing, so repairs should consider how they affect emissions readiness.
  • A possible OEM/open-source interpretation: An open-source definition repository lists P1119 as (Exhaust Absolute Temperature Sensor - High Input). This is one potential mapping for P1119 found in an open-source context; OEM mappings may differ. Treat this as a possible meaning rather than a universal one.

What This Code Means

• P1119 is not universally defined across all makes/models. It is a manufacturer-specific (P1xxx) code that can relate to a sensor in the exhaust path or related to exhaust gas temperature readings, but the exact sensor and fault condition vary by OEM.
• Symptoms you may see (reported by typical complaints for this class of sensor-related P1xxx faults):
  • MIL (Check Engine Light) illuminated
  • Erratic or reduced engine performance; possible misfires or hesitation
  • Degraded fuel economy or elevated emissions
  • Poor acceleration or power loss
  • In some cases, the vehicle may run normally but store the code as a history/freeze-frame condition
• The exact sensor and circuit involved (in particular, whether it is an exhaust temperature sensor or another exhaust/air/temperature sensor) depends on the OEM's definition. The open-source mapping provides one plausible interpretation, but you must confirm with the service data for the specific vehicle.

Symptom-focused checklist (useful when the MIL is on or when anomalies are observed)

• Commonly reported user complaints to inform symptoms:
  • "MIL on with no obvious driveability issue" but with failed emissions readiness
  • "Engine runs rough or lacks power intermittently"
  • "Fuel economy dropped" or "emissions test fails"
  • "Sporadic idle or stalling under load" (less common but possible if sensor readings affect engine control)
• If you are seeing P1119, expect at least one of the above in many OEM implementations of P1xxx sensor-related exhaust/temperature fault codes.

Diagnostic Approach

1) Verify the fault and collect data

• Use a capable scan tool to confirm the P1119 code and capture freeze-frame data, live data, and any related codes (e.g., other exhaust, air, or sensor codes).
• Note the conditions in which the fault occurs (engine temperature, RPM, load, road speed, ambient temperature). This helps determine if the fault is intermittent or temperature/cycle dependent.
• Check for pending codes and history vs. confirmed codes.

2) Identify the exact OEM meaning for P1119 on the vehicle

• Consult the OEM service information or a factory diagnostic database to confirm what P1119 maps to for that specific model and engine.
• If the vehicle's OEM data does not show P1119, check for any TSBs or dealer communications related to exhaust temperature sensors or related circuits.
• If your source indicates P1119 can mean use that as a starting hypothesis only if the OEM data supports it for the vehicle in question.

3) Visual and mechanical inspection

• Inspect the exhaust temperature sensor(s) and wiring harness(es) for:
  • Wire insulation damage, fraying, or exposed conductors near hot exhaust components
  • Corrosion or bent pins in the sensor connector
  • Loose or poor connections, including grounds
  • Signs of exhaust leaks or misalignment that could affect sensor readings
• Inspect related sensors that feed the engine control module (ECM) if the OEM ties P1119 to a thermally related sensor (e.g., exhaust gas temperature sensor, manifold or intake temperature sensors) to rule out cascading sensor issues.
• Check for aftermarket modifications that could affect sensor placement or readings (e.g., aftermarket exhaust, cat, or heat shielding).

4) Electrical tests (sensor and circuit health)

• Resistance/continuity test: With power removed (battery disconnected or circuits isolated according to safety guidelines), test the sensor signal and reference wires for open or shorted circuits. Compare readings to the OEM specifications if available.
• Signal integrity: Using a multimeter or oscilloscope, monitor the sensor signal while gradually loading the engine (if safe) or during a known test condition to see if the signal is erratic or stuck.
• Heater circuit (if the sensor is heated):
  • Measure heater resistance and compare with the OEM specification.
  • Check for short to power, short to ground, or high resistance indicating a failed heater.
• Ground integrity: Verify the actuator/ECM ground connections for the sensor circuit; a poor ground can mimic a high input or weak signal condition.

5) Sensor diagnostic checks (sensor-specific)

• If the OEM mapping suggests an Exhaust Temperature Sensor (EGT) or related sensor, perform sensor-specific checks per service data:
  • Correct sensor placement and orientation
  • Sensor voltage/current in normal operating range
  • Response time to temperature change
• If multiple exhaust temperature sensors exist (e.g., before and after the catalyst), test all relevant sensors and compare readings to expected differential temperatures across the .

6) System-level checks and environmental considerations

• Exhaust leaks upstream of the sensor can cause incorrect temperature readings; inspect the exhaust upstream/around the sensor for leaks or improper routing.
• If the vehicle uses a turbocharger, check for boost leaks or turbo-related issues that could indirectly affect exhaust temperature readings.
• Verify that the ECM software is up to date and that there are no active reflash campaigns that affect sensor interpretation or emissions monitoring (software/firmware can affect DTC behavior).

7) Corroborating data and cross-checks

• Look for related codes that support a sensor/circuit fault (e.g., other exhaust sensors, oxygen sensors, mass air flow, intake air temperature sensors) to confirm a systemic electrical/circuit issue versus a single-sensor fault.
• Check live data for trends: is the exhaust temperature reading abnormally high or stuck at a high value? Is the sensor heater circuit active or inactive as expected?

8) Repair actions (based on findings)

• If the exhaust temperature sensor is confirmed faulty (sensor itself or its heater):
  • Replace the sensor with the OEM part and re-check wiring/connectors.
  • Apply the proper torque specification and ensure correct installation to prevent future readings from drifting.
• If wiring/connectors are the issue:
  • Repair or replace damaged wiring harnesses, re-pin as needed, and ensure solid electrical connections.
  • Re-crimp or replace damaged connectors, and apply dielectric grease as recommended by OEM guidelines.
• If exhaust leaks or misfit components contribute to erroneous readings:
  • Repair leaks, reposition sensors if necessary, and ensure proper sealing around the sensor and exhaust components.
• If ECM/software is implicated:
  • Check for OEM software updates; apply reflashes as instructed by the OEM.
• If no fault is found in the sensor or wiring after thorough checks:
  • Consider PCM/ECM fault or intermittent sensor readings; consult OEM diagnostics for advanced tests or dealer-level procedures.
• After any repair, clear codes and perform a complete drive cycle to ensure the P1119 does not reappear and that emissions readiness monitors behave correctly.

9) Verification and test drive

• Clear the codes and drive the vehicle under normal operating conditions, including a mix of idle, city, and highway driving to confirm the fault is resolved.
• Re-scan to verify no new codes have appeared and that the P1119 did not return as a pending or stored code.

Tools Needed

• OBD-II scan tool capable of live data and freeze-frame capture
• Digital multimeter (DMM) for resistance and continuity checks
• Infrared thermometer or thermocouple for verifying sensor readings and exhaust temps
• OEM service manual for:
  • Sensor location, pinout, and electrical specs
  • Sensor heater circuit specs
  • Expected exhaust temperature ranges and pressure/flow considerations
• Basic safety equipment: gloves, eye protection, and awareness of hot exhaust components; disconnect battery safely when required and follow safe handling when working near the exhaust system

Safety Considerations

• Work with the engine and exhaust components cool whenever possible; hot surfaces can cause severe burns.
• When testing electrical circuits near the exhaust, take care to prevent shorts that could cause electrical hazards or damage to ECM/ECU.
• If the vehicle is under warranty or if there is any doubt about the exact OEM procedure, use OEM service information or the dealer service portal to avoid misdiagnosis.
• Follow all applicable safety practices for working in the automotive environment, including disconnecting power when required and using proper PPE.

Interpretation notes and limitations

• The exact P1119 meaning is OEM-specific. The open-source mapping that lists is one possible interpretation but is not universal. Always confirm the OEM definition for the vehicle you are diagnosing.
• Because P1xxx codes are manufacturer-specific, you may see different fault conditions for the same code number in other brands. Use the vehicle's service data to verify the intended meaning and the recommended diagnostic procedures.

Brief reference points

• DTCs and their role in OBD-II and vehicle diagnostics: Wikipedia OBD-II - Diagnostic Trouble Codes (general concept and importance of DTCs)
• Powertrain code scope: Wikipedia OBD-II - Powertrain Codes (P1xxx family context)
• Emissions testing considerations: Wikipedia OBD-II - Emissions Testing (codes' role in emissions readiness)
• Open-source mapping for P1119: OBD2 CODE DEFINITIONS (title suggests Exhaust Absolute Temperature Sensor - High Input) as a possible interpretation; OEM verification required

This diagnostic guide was generated using verified reference data:

• Wikipedia Technical Articles: OBD-II
• Open-Source OBD2 Data: N/A (MIT)

Content synthesized from these sources to provide accurate, real-world diagnostic guidance.

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