Comprehensive diagnostic guide for OBD-II code P0692

Based on verified sources, plus typical field experience. OEM-specific definitions can vary, so treat this as a robust, generalized guide with notes on variations.

1) Code at a glance

• Code: P0692
• Likely description (per open-source definition linked to the MIT repository): High signal of the fan 1 control circuit (i.e., the PCM detected a high (voltage) condition on the fan 1 control circuit when it shouldn't be, or a fault in the circuit that presents as a high state).
• System: Powertrain (engine management) with effects on cooling fan operation.
• Source notes:
  • OBD-II/Powertrain code families and DTC concepts are described in Wikipedia's OBD-II sections (Diagnostic Trouble Codes, Powertrain Codes) which define how DTCs are used by the PCM to monitor parameters (useful for context).
  • The specific mapping for P0692 as (Fan 1 control circuit high) (MIT/Open Source repository). Keep in mind OEMs may have slightly different naming for P0690-P0693 family codes (some variants use "malfunction," others specify "high/low" control), so confirm with the vehicle's service information if needed.
  • Emissions/Powertrain context is covered by the general OBD-II references (P0692 is a powertrain code and part of the Fan Control circuit subfamily).

2) Common symptoms a customer might report

• Cooling fan behavior changes:
  • Fan runs continuously or comes on at unusual times (even when engine is cool) or stays on high after engine shutdown.
  • Fan does not come on when engine temperature rises (overheat scenario) once the PCM detects a fault.
• Engine temperature/AC impact:
  • Engine overheats or runs hotter at idle or during hot weather due to improper fan control.
  • A/C performance reduced when the cooling system can't reliably pull heat when demanded.
• MIL/Check Engine Light on:
  • Engine light on with code P0692 stored or pending.
• Other related codes may be present (P0690, P0691, P0693, etc.), depending on OEM coding and diagnostic history.

3) Probable causes and rough likelihood

• Faulty cooling fan relay or wiring (high probability, 25-40%)

  • Causes: welded contacts, sticking relay, corroded terminals, shorts to power or ground in the fan circuit wiring.

• Damaged or corroded fan control harness/connector (high) 20-35%

  • Causes: damaged insulation, loose/mis seated connectors, bent pins, moisture intrusion.

• PCM output driver fault or internal condition (moderate) 15-25%

  • Causes: failing transistor/driver in the PCM that drives the fan circuit high.

• Short to power or ground in fan circuit (low-moderate) 10-20%

  • Causes: wiring chafing against engine bay metal, harness routing rubbing through, or a compromised ground path.

• Faulty fan assembly (low-moderate) 5-15%

  • Causes: a physically seized fan that causes load/current anomalies and triggers control-circuit protection/monitoring.

• Other related sensor/ECU inputs (low) 5-10%

4) Tools and safety notes

Safety Considerations

• Work around hot engine components and moving fans. Ensure engine is cool before starting work if you're going to inspect wiring or fans manually.
• Disconnect the battery (negative lead) if you'll be unplugging connectors or performing any wiring work with the engine off, and then re-connect after inspection if necessary.
• PPE: gloves, eye protection when inspecting underhood.

Tools Needed

• OBD-II scan tool with live data and ability to command/poll fan control (if supported by the vehicle).
• Wiring diagram for radiator fan circuit (to identify relay/fuse/ground paths and the fan connectors).
• Multimeter (digital) for voltage, resistance, and continuity checks.
• Test light or temp probe (optional).
• Replacement parts as needed (relay, fuses, connectors, possibly the fan itself).

5) Diagnostic flow (step-by-step)

Goal: Confirm whether the issue is a wiring/relay fault, a PCM output fault, or a fan motor fault, and then repair accordingly.

Step 0: Verify and scope

• Retrieve all codes with freeze-frame data and any related DTCs (P0690, P0691, P0693, etc.). Note any temperature data or RPM data in the data stream.
• Confirm the customer complaint aligns with the symptom set (e.g., fan on continuously, overheating, poor A/C).

Step 1: Visual and basic electrical checks

• Inspect the cooling fan harness and connectors for damage, corrosion, or moisture.
• Inspect the fuse(s) and the cooling fan relay. Replace if damaged or suspect; test the relay coil resistance and contact closure with the appropriate circuit powered.
• Look for obvious wiring damage (chafing, pin corrosion, loose grounds) around the fan, relay, and fuse box.

Step 2: Verify power and ground at the fan

• With engine off, backprobe the fan control circuit at the fan connector to check:
  • The control circuit voltage (should be near 12V when the PCM commands high, or during a fault state if the code is stored).
  • The ground path (continuity to chassis ground).
• With engine on and temperature rising (or commanded by the scan tool if it can command fan), observe:
  • Does the fan engage when commanded? Is the signal at the fan control circuit going high as the PCM commands? Is the fan voltage present?
  • If the fan does not run when commanded, the fault could be in the relay, wiring, or the fan itself.
• If the circuit shows a constant high or a short to power, investigate the insulation and pin integrity in the wiring harness and the relay contacts.

Step 3: PCM output verification (if equipment allows)

• Using an oscilloscope or a capable scan tool, monitor the fan control output line to see if the PCM is:
  • Generating a proper PWM or high/low command as expected for the given temperature.
  • Stuck high or receiving erroneous inputs causing the PCM to set P0692.
• Check for CAN/communication faults if the vehicle uses CAN to coordinate fan control (some platforms rely on ECM/PCM messages rather than a direct PWM line).

Step 4: Component-level checks

• If wiring and PCM outputs appear correct, check the radiator fan motor itself:
  • Apply 12V directly to the fan via a fused jumper to see if the fan spins reliably (bypassing the PCM circuit). If the motor fails to run, the fan motor is likely defective.
• If the fan runs when directly energized but not when commanded by PCM, suspect the control circuit (relay, wiring, or PCM output path) rather than the motor.

Step 5: Synthesize results and decide

• If the fan runs when directly energized but not when commanded by the PCM, focus on the control circuit wiring/relay or PCM output.
• If wiring/relay tests indicate integrity, but PCM output appears stuck or erratic, consider PCM fault or ECU software update as a possibility (with OEM guidance).
• If the fan motor is defective or physically jammed, replace the fan assembly.

6) How to confirm the repair

• Clear the stored codes.
• Start the vehicle and monitor live data (temperature, fan status, RPMs, and duty-cycle/command signals) to ensure:
  • The fan cycles on/off at appropriate temperatures.
  • The P0692 code does not reoccur after a short drive (15-20 minutes with a few cycles of temperature rise).
• Perform a test drive across expected operating conditions (idle, light load, higher speeds, and hot ambient conditions) to verify stability.

7) Typical fixes and parts replacement

• Wiring/connector repair:
  • Replace damaged wiring harness sections; reseat or replace corroded connectors; clean grounds.
• Relay and fuse:
  • Replace faulty cooling fan relay; inspect fuse and fuse block contact cleanliness; replace blown fuses.
• Fan assembly:
  • Replace the cooling fan motor or complete assembly if motor is seized or defective.
• PCM (as a last resort or after OEM guidance):
  • Replace or reprogram the PCM if confirmed as the source of the faulty control signal and no wiring faults are present (this is less common and should be guided by OEM procedure).

8) Additional notes and caveats

• OEM variations: The DTC P0692 is part of the P0690-P0695 family. Some manufacturers label these as "Fan 1 Control Circuit High/Low," "Fan 2 Control Circuit Malfunction," etc. The MIT/open-source definition explicitly describes P0692 as the Always consult the specific OEM service information for your vehicle to confirm the exact definition and test procedures.
• Related codes: If P0692 appears with other coolant/fan-related codes, address those together as they may point to common root causes (relay, wiring, or PCM output).
• Emissions context: As a powertrain/engine cooling control code, P0692 is a diagnostic code that can affect readiness monitors and emissions-related checks indirectly by affecting operation of the cooling system. It is not an emissions device fault itself, but it can influence heat management and catalyst efficiency under certain conditions.

9) Quick-reference checklist

• Symptoms align with P0692 (fan circuit high) and/or fan behavior anomalies.
• Visual/Wiring: Inspect wiring to fan/relay; check harness for damage or corrosion.
• Fuses/Relays: Confirm fuse integrity and relay operation; replace if suspect.
• Electrical tests: Verify fan control circuit voltage and ground; confirm PCM output signal behavior.
• Motor test: Verify fan motor operation when directly energized.
• Post-repair: Clear codes; drive in varied conditions and verify no reoccurrence.

10) Sources and notes

• General DTC and OBD-II framework: Wikipedia, OBD-II sections on Diagnostic Trouble Codes and Powertrain Codes (for context on how DTCs work and the powertrain focus).
• Specific code interpretation used here: Open-source code definition mapping P0692 to . This mapping is provided as a standard reference for what P0692 commonly represents in open-source repositories; OEMs may differ in exact phrasing, so confirm via factory service data.
• Handling notes: The OBD-II DTC framework is used to monitor powertrain parameters and trigger a MIL when thresholds are exceeded; P0692 falls under the Fan Control circuit family, meaning the issue is related to the PCM's fan control output or the fan circuit itself, rather than a temperature sensor in isolation.

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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