Comprehensive diagnostic guide for OBD-II code P1190

Important Notes

• P1190 is not listed as a universal, SAE-standard DTC . The standard OBD-II DTC set (P-codes) is explained in general terms, with "P" representing powertrain codes and a diagnostic approach applicable across many vehicles. However, the exact meaning of P1190 can be vehicle- or OEM-specific.
• An open-source entry is shown for a code described as "Calibração resistor fora da faixa" (Calibration resistor out of range). This is not a standard, widely adopted definition for P1190 and may reflect a non-standard or OEM-specific interpretation. Treat such open-source mappings as not universally applicable to P1190 and verify via OEM service information if encountered.
• Given the lack of a canonical, vehicle-agnostic definition for P1190 , the diagnostic process below emphasizes a safe, systematic approach: confirm the code, gather data, check for OEM definitions, inspect wiring and sensors, and verify repair. When vehicle-specific meaning exists, prioritize OEM documentation.

1) What P1190 likely means (context and limitations)

• Standard OBD-II framework: P-codes are powertrain faults; P1xxx codes are generic, while P2xxx codes are manufacturer-specific. The exact condition that triggers P1190 is not defined in the provided general references. This means:
  • If you see P1190, first check the vehicle's OEM diagnostic information (service manual, manufacturer scan tool definitions, TSBs) to confirm the exact fault description.
  • If OEM data are not readily available, treat P1190 as a powertrain fault that could involve a sensor, calibration/threshold issue, or ECU interpretation that is not part of the generic OBD-II set.
• A non-standard or OEM-specific P1190 may reference sensor calibration, resistance checks, or a particular circuit in the PCM/sensor network. The open-source entry mentions "Calibration resistor out of range" but it is not a universal definition for P1190. Use OEM data for exact meaning.

2) Common symptoms you might observe (user complaint-oriented)

• Malfunction Indicator Light (MIL) illuminated or steady MIL
• Intermittent or persistent engine performance issues such as:
  • Rough idle or misfire-like sensation
  • Hesitation or lack of power under load
  • Poor throttle response or stumble during acceleration
  • Reduced fuel economy or unusual fuel trim values on scan
• Difficulty starting or stumble during cold/hot starts (depending on the underlying circuit)
  Note: Symptoms can vary widely depending on the actual OEM meaning of P1190 and the affected subsystem. Always correlate live data and OEM definitions.

3) Required tools and safety precautions

• OBD-II scan tool capable of reading standard P-codes and, if possible, OEM-enhanced codes
• Vehicle service information (OEM manufacturer data, dealer tool access, or OEM TSBs) for P1190 meaning
• Multimeter, scan tool live data capabilities, oscilloscope if available for signaling/wiring checks
• Fuel pressure gauge, vacuum/EVAP test equipment if subsystem inspection suggests fuel or intake issues
• Personal protective equipment and standard shop safety: disconnect battery when performing electrical tests where appropriate; avoid shorting circuits; prevent exposure to hot components

4) Diagnostic approach (step-by-step workflow)

Step 1: Confirm and document

• Retrieve the DTC with an appropriate scan tool. Note:
  • DTC status (pending vs. confirmed)
  • Freeze frame data (engine RPM, vehicle speed, fuel trims, MAF/MAP readings at the time of fault)
  • Any other codes present
• If the code is not reproducible or disappears after a drive cycle, document the behavior and re-check after varying conditions.

Step 2: Verify OEM meaning

• Look up the exact P1190 description in OEM service information for the specific make/model/year. If OEM data are unavailable, proceed with a fault-finding approach based on common powertrain fault patterns and sensor circuits, keeping in mind this may be speculative without OEM mapping.
• If other, more common DTCs accompany P1190, address those first as they may reveal a primary fault (e.g., sensor circuit faults, misfire codes, or fuel system issues).

Step 3: Inspect for obvious electrical and wiring issues

• Visual inspection of wiring harnesses and connectors related to the suspected subsystem (sensor circuits, calibration networks, or PCM connections).
• Check grounds and battery voltage with engine off and during cranking; ensure stable 12-14 V operation; look for voltage dips.
• Look for corrosion, loose terminals, damaged insulation, or pin damage in harnesses.
• If the open-source reference mentions calibration resistors in a circuit, consider checking any resistive networks or pull-up/pull-down resistors in that circuit, but only as guided by OEM data.

Step 4: Analyze live data and sensor behavior

• Use the scan tool to monitor relevant signals in real time (voltage/current, resistance, heater circuits if applicable, sensor output, etc.).
• Compare sensor readings to known-good ranges from the OEM data or service manual. For a non-standard P1190, this often points toward:
  • Sensor input circuits (voltage/ground integrity)
  • Calibration or reference signals used by the ECU
  • Any circuit that relies on a resistive network
• Note anomalies such as out-of-range voltages, erratic readings, or stuck sensor values.

Step 5: Functional tests for plausible fault areas

• If OEM data indicate a sensor or resistor/calibration network is implicated, perform targeted tests:
  • Sensor input tests (verify same signal with alternate sensors if possible)
  • Resistance checks in known calibration circuits (with power removed)
  • Wiring continuity and insulation tests
  • PCM/ECU communication integrity (CAN bus or other networks) if OEM data suggest comms issues
• Perform fuel/air subsystem checks if the symptom set indicates a fuel or air calibration problem (fuel pressure, MAF/MAP readings, injector circuit integrity, etc.). While not specifically defined by P1190 , these are common powertrain fault areas.

Step 6: OEM data-informed repair paths

• If OEM documentation identifies a specific failed component or wiring path for P1190, perform the repair as specified (component replacement, wiring repair, or PCM/firmware update).
• If the OEM defines calibration thresholds or resistor-related calibration requirements, perform those calibration steps per the service information.
• After any repair, clear codes, perform a drive cycle, and re-check to confirm the code does not return.

Step 7:Verification and documentation

• Re-scan to confirm no DTCs are present.
• Verify that all related data (fuel trims, sensor readings) have returned to normal ranges.
• Document the diagnostic steps, findings, part replacements, and test results for future reference.

5) Probable causes and estimated likelihood

Note: There are no NHTSA data points for P1190 . The following probabilities reflect general field experience with nonstandard OEM codes and powertrain fault scenarios. They are presented as ranges to reflect variability across makes and models.

• Wiring/connectors in the implicated circuit (harness damage, poor ground, connector corrosion)
  • Estimated likelihood: 25-40%
• OEM-specific meaning of P1190 (calibration/resistor network, sensor calibration or circuit-specific fault)
  • Estimated likelihood: 25-40%
    Reasoning: OEM-specific codes often arise from calibration, reference signals, or circuit thresholds not covered by generic DTCs.
• Sensor or actuator in the implicated circuit (faulty sensor, intermittent signal, heater/driver circuit issues)
  • Estimated likelihood: 15-25%
• ECU/PCM software or calibration mismatch (outdated software, corrupt calibration data)
  • Estimated likelihood: 5-15%
• Secondary issues (fuel delivery, vacuum leaks, emissions system faults) that could trigger related symptoms that resemble P1190
  • Estimated likelihood: 5-10%

Notes:

• The above distributions are provided to guide troubleshooting efficiency in the absence of a universal P1190 definition and NHTSA complaint data for this code. They reflect typical OEM-code diagnostic experiences where calibration networks and sensor wiring frequently cause OEM-specific DTCs, often more so than a single failed sensor.
• If OEM data identify a distinct, defined cause for P1190 for this vehicle, prioritize that interpretation over the generic percentages.

6) Data collection and symptom mapping (practice tips)

• Record exact DTC text as delivered by the OEM scan tool (e.g., P1190 description, any supplemental information).
• Save freeze-frame data: RPM, speed, coolant/air temperatures, fuel trims, MAF/MAP values, sensor voltages.
• Capture live data across drive cycles to observe how values change with engine load, speed, and temperature.
• If the code reappears after clearing, note the driving conditions when it reappears (idle, highway, city stop-and-go).

7) Safety and caution

• When testing suspect circuits or sensors, avoid applying power to circuits with suspected shorted wires; use protective equipment and proper testing procedures.
• If there is a risk of fuel system issues, follow appropriate safety protocols for fuel pressure testing and ignition-off electrical tests.
• When in doubt about OEM procedures for P1190, defer to OEM service information and use dealer-grade tooling.

8) Quick reference cheat sheet

• Determine if P1190 is OEM-defined for the vehicle and obtain the exact description from OEM data.

• Check for multiple related DTCs first; address easier, more common faults (e.g., wiring, grounds) that can cause shared symptoms.

• Use live data to confirm whether the circuit involved is within expected ranges; pay particular attention to resistance, voltage, and sensor signals tied to the suspected calibration network.

• If calibration/resistor networks are implicated by OEM data, perform the prescribed calibration steps or component replacement per OEM guidelines.

• After repair, perform a complete drive cycle and re-scan to confirm codes are cleared and performance returns to normal.

• General OBD-II DTC concepts and the P-code family context: Wikipedia - OBD-II, Diagnostic Trouble Codes; Wikipedia - OBD-II, Powertrain Codes. These sources explain that DTCs are used to monitor parameters and that P-codes are associated with powertrain issues.

• Open-source entry mentioning "Calibração resistor fora da faixa" (Calibration resistor out of range), illustrating that some non-standard mappings exist in open datasets; this reinforces the need to verify P1190 against OEM data rather than assuming a universal meaning.

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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