P1335 — EGR Performance at Minimum Throttle Position

Does P1335 always mean the EGR valve needs replacement?

No. P1335 identifies an EGR performance deviation while the throttle-position signal is at minimum, and carbon restriction, a vacuum leak, a control-solenoid fault, or an inaccurate position signal can all set it.

Can I continue driving with P1335 stored?

Usually, yes, but the vehicle may idle roughly, hesitate, run less efficiently, or fail an emissions test. Avoid extended driving if P1335 is accompanied by severe stalling, smoke, or major power loss.

Will clearing the P1335 code repair the vehicle?

No. Clearing P1335 only resets the monitor and may turn off the check-engine light. If the underlying EGR or throttle-position fault remains, the code commonly returns during a later drive cycle.

What live data should be checked for P1335?

Use an ELM327 adapter with AIScanAuto or another scanner to compare accelerator/throttle-position data with EGR commands and, where supported, actual EGR position or flow response. Test capability varies by vehicle.

When your vehicle's engine control unit detects that a sensor or actuator circuit is not responding within its expected parameters, it logs trouble code P1335. This diagnostic alert tells you that somewhere in the affected circuit, the electrical signals have strayed outside the factory-calibrated range the ECU expects to see during normal engine operation.

Modern engines rely on a constant conversation between sensing devices and controlling actuators. The ECU sends commands and receives feedback; when that feedback does not match what the computer expects, P1335 gets triggered. The module typically needs to see this discrepancy occur across multiple drive cycles before it commits the code to permanent memory. Once triggered, the ECU also captures a freeze frame snapshot—recording engine speed, load percentage, coolant temperature, and vehicle speed at the exact moment the fault was detected. That snapshot is your most valuable starting point for diagnosis, because it tells you what conditions were present when the system misbehaved.

Common Symptoms of P1335

P1335 manifests differently depending on which circuit has failed. Watch for these signs:

• The Check Engine light illuminates on your dashboard
• The affected system operates inconsistently or stops functioning entirely
• Fuel economy drops noticeably in some vehicle applications
• The engine may enter limp-home mode, limiting power and speed
• Performance feels sluggish or unresponsive under load
• Acceleration may hesitate or stumble during throttle input
• In rare cases, the vehicle refuses to start until the fault is cleared

What Causes P1335?

Several root causes can trigger P1335, ranging from simple wiring issues to complete component failure:

• A failed or degrading sensor or actuator within the problem circuit ranks as the most frequent culprit
• A blown fuse protecting the affected circuit interrupts power and sets the code
• The control module's internal driver circuitry can fail, preventing proper signal output
• Corrosion, rust, or looseness at ground connections creates erratic reference voltages
• Wiring insulation cracks from age, heat cycles, or road debris expose bare conductors
• Connector pins spread or break, causing intermittent contact under vibration
• Aftermarket accessories wired incorrectly can feed phantom signals back into the circuit

How to Diagnose P1335

Follow this structured approach to pinpoint the failure without replacing parts unnecessarily:

1. Plug in an OBD2 scanner, retrieve P1335, and record all stored freeze frame data before clearing anything. Note the engine conditions when the fault occurred.
2. Scan for any other trouble codes present at the same time. Related codes often point directly to the failing component. Also search manufacturer TSB databases using your VIN—many P0xxx codes have documented factory fixes or calibration updates.
3. Perform a thorough visual inspection of the wiring harness and connectors tied to the problem circuit. Look for damaged insulation, green corrosion buildup, melted plastic, or pins that appear burnt or pushed out of position.
4. Use a multimeter to verify reference voltage, ground integrity, and signal continuity at the component's electrical connector. Compare readings against manufacturer specifications.
5. Conduct a wiggle test on the harness while monitoring live data on your scanner. Any signal dropouts or wild fluctuations indicate broken wires inside the insulation that flex with movement.
6. Clear P1335 and complete a full drive cycle that reproduces the freeze frame conditions—similar rpm, load, temperature, and speed. If the code reappears, you have confirmed an active fault and can proceed confidently to repair.

Repair Options and Costs

Address the least expensive possibilities before committing to major component replacement:

• Wiring harness repair or connector replacement: $80–$250
• Control module diagnosis and repair: $300–$1,000
• Sensor or actuator replacement (parts and labor): $150–$500

The total bill for resolving P1335 typically falls between $80 and $1,000 depending on which part failed. An honest diagnosis upfront prevents buying expensive components you do not need. The priciest scenario—module repair—is rarely the first thing to check.

Can You Drive with P1335?

Most vehicles remain operational after P1335 sets, though you may notice diminished performance or a non-functional auxiliary system. Reduced throttle response and slightly higher fuel consumption are common. Treat the fault as urgent if you experience stalling, a no-start condition, or warnings affecting your brakes and power steering. Otherwise, schedule repairs within a few days rather than weeks.

Related OBD2 codes

• P1300: Multi-faults - Bank 1 - With Low Side Shorts
• P1301: Multi-faults - Bank 2 - With Low Side Shorts
• P1302: Injector High Sides Shorted Together
• P1303: IDM Failure
• P1304: Cylinder Head Overtemperature Protection Active
• P1305: Boost Calibration Fault