P1661moderate severityPowertrain
EGR Circuit Malfunction
on 2008 Toyota Highlander 3.5L V6 · AWD
What this code means
The ECM detected a fault in the EGR system control circuit.
Symptoms
- CEL
- Rough idle
- Hesitation
- Increased NOx
- Failed emissions
Common causes
- Faulty EGR solenoid
- Carbon clogged passages
- Damaged wiring
- Vacuum leaks
Diagnostic steps
- Test EGR solenoid
- Clean EGR passages
- Inspect wiring
- Check vacuum supply
Repair notes
Clean or replace EGR components.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1