Comprehensive diagnostic guide for OBD-II code P0699 Note: The exact meaning of P0699 can be manufacturer-specific. The sources provided do not contain a universal, vehicle-wide definition for P0699. Use factory service information for your specific vehicle once available.

1) What the sources say about OBD-II codes (context for P0699)

• OBD-II codes are diagnostic trouble codes used by modern vehicles to indicate faults detected by onboard controls. DTCs are part of a standardized system, with Powertrain Codes (P0xxx) covering most engine, transmission, and related systems. This foundation helps frame how P0699 fits into a broader diagnostic workflow.
• The powertrain code family (P0xxx) is specifically associated with engine and drivetrain control systems, as opposed to emissions service, body, or chassis codes. This informs the general approach to diagnosing P0699.
• An open-source entry in Portuguese mentions a potential interpretation related to a . This is not a universal definition for P0699, but demonstrates that some OEM/alternate-code mappings may use sensor-reference-voltage conditions as the code's descriptor in certain contexts. Treat this as a possible interpretation rather than a universal definition.

2) Practical implications for P0699

• Since the exact manufacturer-specific meaning of P0699 is not defined , treat P0699 as a Powertrain (P0XXX) DTC and start with a methodical, fault-tree approach rather than assuming a single component. The diagnostic steps below emphasize power, relay circuits, control outputs, and related wiring, which are common culprits for P0XXX relay/control-type codes.

3) Common symptoms you might see (user-reported complaints to inform symptom descriptions)

• No-start or hard-start, especially when cranking for extended periods.
• Intermittent starting problems (cranks but sometimes fails to start).
• Starter intermittently does not engage or remains cranked without a proper engine start.
• Engine runs poorly or stalls if the vehicle starts but cannot maintain idle.
• Check Engine light (MIL) illuminated with DTC P0699 stored or pending, possibly alongside other P0XXX codes.
  Note: These symptom patterns are typical in powertrain-related relay/control issues and align with the general behavior described by powertrain DTCs, though this is not a vehicle-specific definition of P0699.

4) Quick diagnostic workflow (outline you can follow on the bench or in the bay)

• Confirm the code and data
  • Use a scan tool to confirm P0699 is present and retrieve freeze-frame data, readiness monitors, and any related live data (voltage, relay states, etc.).
  • Note vehicle make/model/year and any related DTCs that appear with P0699; this helps narrow manufacturer-specific meaning.
• Vehicle readiness and battery health
  • Check battery condition and charging voltage (should be ~12.6V with engine off, ~13.8-14.8V with engine running).
  • Inspect grounds and battery-to-chassis/engine ground straps for corrosion, looseness, or damage.
  • Inspect fuses and fusible links related to the starter, relay circuits, and ignition (these are common points of failure in powertrain DTCs).
• Focused fault-hypothesis areas for P0699 (based on the "powertrain/relay" family approach)
  • Starter relay circuit and related wiring
    • Verify that the starter relay is receiving a proper control signal from the PCM/ECU when cranking.
    • Measure coil voltage at the relay and confirm the relay is actually energizing (the coil should show ~12V when commanded, with a corresponding audible/visual indication or a connected test lead showing supply).
    • Check for high resistance or corrosion at relay sockets, and confirm the relay contacts are not welded or sticking.
  • Power supply to the starter and essential circuits
    • Inspect the main power supply to the starter circuit (fuel pump/ignition circuits may share relays) for proper voltage delivery when cranking.
    • Look for excessive voltage drop in wiring to the starter, which can mimic a relay problem.
  • Engine control module (ECM/PCM) outputs
    • When cranking, confirm the PCM is issuing the correct control signal to the starter relay (and any other relay involved in the starting circuit). A lack of signal could indicate a PCM fault, an input signal issue (e.g., ignition switch, neutral safety switch), or a communication fault.
  • Ignition switch and safety interlocks
    • For automatics: ensure the transmission is in Park or Neutral as the system expects. A faulty neutral safety switch or shift interlock can prevent relay output from energizing.
    • For manuals: verify clutch safety switch and related wiring if applicable.
  • Ground integrity and high-current paths
    • Inspect battery-to-ground circuits and chassis grounds near the starting circuit for corrosion or looseness, which can cause intermittent starting problems and misinterpretation of DTCs.
• Emissions and readiness considerations
  • If you are performing OBD-II readiness checks, ensure other monitors are in a compatible state; some P0XXX codes can be associated with other sensor or control failures that influence starting/alternator-load behavior.

5) Diagnostic testing steps and expected observations

• Step 1: Battery and first-prong checks

  • Test battery voltage at rest and during cranking; look for a significant voltage drop under load. If voltage collapses, the problem may be battery or alternator-related rather than a relay fault.

• Step 2: Relay and wiring test

  • Access the starter relay (and any relevant powertrain relays) and test coil resistance per service data.
  • Command the relay on/off with the scan tool if possible; listen for a click and verify the circuit is energizing. Use a multimeter to verify contact continuity when energized.
  • Inspect harness connectors for corrosion, bent pins, or bent tangs; reseat or swap with a known-good relay if needed.

• Step 3: Starter circuit voltage tracing

  • With the relay energized, verify the voltage at the starter motor input. If voltage is present but the starter does not engage or the engine cranks poorly, the issue could be starter/solenoid mechanical failure or excessive resistance in the harness.

• Step 4: PCM output verification

  • Using a scope or data stream, confirm that during cranking the PCM provides the expected signal to the relay coil. If the PCM is not providing the signal, investigate input signals to the PCM (crank/cam sensors, immobilizer data, ignition switch state) and the integrity of the CAN/serial communication networks if applicable.

• Step 5: Mechanical starter check

  • If voltage and control signals look correct but the engine does not crank or the starter drags, inspect or bench-test the starter and solenoid. A stuck or weak starter can produce symptoms that trigger P0xxx codes due to abnormal current draw or voltage drop.

• Step 6: Re-check after repair

  • Clear codes (after repair) and re-test starting condition to confirm DTC does not recur. Re-check readiness monitors.

• Relay, fusible links, or wiring issues in the starting circuit (most common for P0699-type symptoms): 40-60%

• Battery, charging system, or poor grounds causing voltage drops during cranking: 20-30%

• PCM/ECM control output fault or software issue affecting relay drive: 5-15%

• Ignition switch, neutral/clutch safety interlocks, or transmission gear position detection faults: 5-10%

• Mechanical starter or solenoid failure (sticking/weak actuation): 5-10%
  Note: These percentages are approximate field estimates. They reflect typical patterns seen for powertrain/relay-related codes when the exact manufacturer description of P0699 isn't available .

7) Safety considerations

• Disconnect the battery before servicing high-current relays, the starter, or heavy wiring to avoid arcing or electric shock.
• When testing with live circuits, use insulated tools and proper PPE; be aware of hot engine components and moving parts.
• If you must crank the engine during testing, ensure the vehicle is in a safe, stable condition to prevent unintended movement.

8) Additional notes and caveats

• do not give a universal, vehicle-wide definition for P0699. Use the manufacturer's service information to confirm the exact P0699 definition for your vehicle (some systems map P0699 to a specific starter-relay or power-relay condition, while others may map it to different relay-related faults or sensor references).
• An Open Source entry in Portuguese mentions as a possible interpretation; treat this as a potential clue for some systems but not a universal definition. Always cross-check with OEM diagnostics and wiring diagrams for your vehicle.
• If you encounter P0699 in a vehicle and the steps above do not locate a fault, consider:
  • A failed PCM output module or communications fault.
  • A high-resistance path in the starting circuit causing intermittent voltage drops not captured by simple voltage checks.
  • A vehicle-specific issue reported by the manufacturer, requiring factory scan tools and programming/flash updates.

9) Documentation and reporting

• Record all measured values (battery voltage, relay coil resistance, contact voltage, harness resistance, ground integrity, and PCM output signals).
• Note the exact location of relays, fuses, and connectors inspected.
• Document the crime scene: weather, vehicle age, mileage, and any associated symptoms (cranks, starts, stalls) with timestamps.
• After repair, re-scan for codes, verify readiness, and confirm the starting condition under various loads (hot/cold starts, after idle, etc.).

10) Summary

• P0699 is a Powertrain (P0XXX) code; the exact meaning is vehicle-specific. Given the sources, treat P0699 primarily as a power/relay-related fault affecting starting or related control circuits.
• A structured diagnostic path focusing on the starter relay circuit, wiring, battery/ground integrity, PCM control outputs, and safety interlocks provides a robust approach to identify the root cause.
• Where manufacturer-specific information is unavailable , rely on vehicle-specific factory data and general electrical troubleshooting best practices to confirm the fault and implement a repair.

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.

---