LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Honda >> 2007 >> Ridgeline RT >> Repair and Diagnosis >> Engine Performance >> Fuel Delivery >> Fuel And Emissions Systems >> Symptom Troubleshooting Index
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Symptom Troubleshooting Index

When the vehicle has one of these symptoms, check for a diagnostic trouble code (DTC) with the HDS. If there is no DTC, do the diagnostic procedure for the symptom, in the sequence listed, until you find the cause.

SYMPTOM TROUBLESHOOTING CHART

Symptom Diagnostic procedure Also check for
Engine will not start (MIL works OK, no DTCs set)
  1. Test the battery (see BATTERY TEST ).
  2. Test the starter (see STARTER SOLENOID TEST ).
  3. Check the fuel pressure (see FUEL PRESSURE TEST ).
  4. Troubleshoot the fuel pump circuit (see FUEL PUMP CIRCUIT TROUBLESHOOTING ).
  • Low compression
  • No ignition spark
  • Intake air leaks
  • Locked up engine
  • Broken timing belt
  • Contaminated fuel
Engine will not start (MIL comes on and stays on, or never comes on at all, no DTCs set) Troubleshoot the MIL circuit (see MIL CIRCUIT TROUBLESHOOTING ).
  • Low compression
  • No ignition spark
  • Intake air leaks
  • Locked up engine
  • Broken timing belt
  • Contaminated fuel
  • No power to PCM
  • No ground to PCM
  • Shorted reference voltage
MIL comes on and stays on, or never comes on at all, no DTCs set Troubleshoot the MIL circuit (see MIL CIRCUIT TROUBLESHOOTING ).  
Engine will not start (MIL works OK, no DTCs set, immobilizer indicator stays on or flashes) Check the immobilizer system.  
Engine starts but stalls immediately (MIL works OK, no DTCs set, immobilizer indicator stays on or flashes) Check the immobilizer system.  
Engine is hard to start (MIL works OK, no DTCs set)
  1. Test the battery (see BATTERY TEST ).
  2. Check the fuel pressure (see FUEL PRESSURE TEST ).
  3. Clean the throttle body (see THROTTLE BODY TEST ).
  • Low compression
  • Intake air leaks
  • Contaminated fuel
  • Weak spark
Cold fast idle too low (MIL works OK, no DTCs set)
  1. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  2. Check the idle speed (see IDLE SPEED INSPECTION ).
  3. Clean the throttle body (see THROTTLE BODY TEST ).
 Incorrect valve adjustment
Cold fast idle too high (MIL works OK, no DTCs set)
  1. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  2. Check the idle speed (see IDLE SPEED INSPECTION ).
  3. Do the throttle position learning check (see THROTTLE BODY TEST ).
 Intake vacuum leaks
Idle speed fluctuates (MIL works OK, no DTCs set)
  1. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  2. Check the idle speed (see IDLE SPEED INSPECTION ).
  3. Do the carbon accumulation check (see THROTTLE BODY TEST ).
 Intake vacuum leaks
After warming up, idle speed is below specification without load (MIL works OK, no DTCs set)
  1. Troubleshoot the alternator FR signal circuit (see ALTERNATOR FR SIGNAL CIRCUIT TROUBLESHOOTING ).
  2. Do the carbon accumulation check (see THROTTLE BODY TEST ).
 Incorrect valve adjustment
After warming up, idle speed is above specification without load (MIL works OK, no DTCs set)
  1. Troubleshoot the alternator FR signal circuit (see ALTERNATOR FR SIGNAL CIRCUIT TROUBLESHOOTING ).
  2. Inspect the APP sensor (see APP SENSOR REPLACEMENT )
 Intake vacuum leaks
After warming up, idle speed drops when steering wheel is turning (MIL works OK, no DTCs set)
  1. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  2. Troubleshoot the PSP switch signal circuit (see PSP SWITCH SIGNAL CIRCUIT TROUBLESHOOTING ).
  3. Do the carbon accumulation check (see CARBON ACCUMULATION CHECK ).
 Power steering system problems
Low power (MIL works OK, no DTCs set)
  1. Check the fuel pressure (see FUEL PRESSURE TEST ).
  • Low compression
  • Incorrect camshaft timing
  • Incorrect engine oil level
  • Restricted exhaust
  • Fuel contamination
Engine stalls (MIL works OK, no DTCs set)
  1. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  2. Check the fuel pressure (see FUEL PRESSURE TEST ).
  3. Check the idle speed (see IDLE SPEED INSPECTION ).
  4. Troubleshoot the brake pedal position switch signal circuit (see BRAKE PEDAL POSITION SWITCH SIGNAL CIRCUIT TROUBLESHOOTING ).
  • Intake air leaks
  • Faulty harness and sensor connections
  • Fuel contaminations
Difficult to refuel (MIL works OK, no DTCs set)
  1. Check the fuel vent tube between the EVAP canister and the fuel tank.
  2. Check the fuel tank vapor recirculation tube between the fuel pipe and the fuel tank.
  3. Inspect the fuel filler neck for restrictions.
  4. Replace the fuel tank unit (see FUEL TANK REPLACEMENT ).
  5. Replace the fuel tank (see FUEL TANK REPLACEMENT ).
 Malfunctioning gas station filling nozzle.
Fuel overflows during refueling (No DTCs set)
  1. Replace the fuel tank unit (see FUEL TANK REPLACEMENT )
  2. Inspect the fuel filler neck for restrictions.
  3. Replace the fuel tank (see FUEL TANK REPLACEMENT ).
 Malfunctioning gas station filling nozzle.
HDS does not communicate with the PCM or the vehicle Troubleshoot the DLC circuit (see DLC CIRCUIT TROUBLESHOOTING )  
scientia non olet · About LEMON Manuals