All Powertrain Speed & Idle DTC Codes — Complete OBD-II Diagnostic Guide (2026)

This comprehensive reference covers every Powertrain Speed & Idle diagnostic trouble code (DTC) — 6 codes total. Each code includes what triggers it, common symptoms, step-by-step diagnostic procedures, and repair guidance.

6DTC Codes
3Medium
3Low

Detailed DTC Code Guides

P0500: The powertrain control module (PCM) has detected that the vehicle‑speed sensor (VSS) is not delivering a valid signal. Without that signal the PCM cannot calculate speed‑related functions, leading to a dead or jumping speedometer, disabled cruise control, and unstable idle.

medium ⏱️ 30‑60 minutes ⚠️ Short trips are possible, but loss of cruise control, erratic idle and potential stalling make long drives unsafe. The fault also causes an automatic emissions‑test failure.

Discover why the P0500 code appears, how it affects your speedometer, cruise control and emissions, and follow a step‑by‑step DIY process with cost...

Diagnostic steps:
  1. Visual inspection of connector and wiring
  2. Live‑data scan of Vehicle Speed (PID 0D)
  3. Freeze‑frame analysis
  4. ...see all 6 steps →
Read full diagnostic guide →

P0505: The engine’s computer has detected that the idle control system is not regulating RPM correctly. This usually means the idle air control valve or its circuitry isn’t responding as it should, causing the engine to idle too high, too low, or to fluctuate.

low ⏱️ 30-60 minutes ⚠️ Yes, you can drive, but expect rough idle and possible stalling.

P0505 signals an idle control system fault. Learn why it happens, quick 60‑second checks, step‑by‑step DIY repair, cost estimates, emissions impact, and...

Diagnostic steps:
  1. Quick Visual Scan
  2. Check for Stored Trouble Codes
  3. Measure IAC Voltage/Resistance
  4. ...see all 7 steps →
Read full diagnostic guide →

P0506: The powertrain control module has detected that the engine's idle speed is below the programmed target. This usually points to a problem with the idle air control (IAC) valve, throttle‑position sensor, or related wiring. When the engine cannot maintain proper idle, it may shake, stall, or surge.

medium ⏱️ 30-60 minutes ⚠️ You can keep driving, but expect rough idle and possible stalling.

P0506 means your engine idle RPM is low. Discover why it happens, how to test the idle air control valve, and get cost estimates for Toyota, Chevy, and more.

Diagnostic steps:
  1. Check for obvious issues
  2. Inspect IAC valve and passage
  3. Test IAC valve operation
  4. ...see all 6 steps →
Read full diagnostic guide →

P0507: The powertrain control module has detected that the engine idle speed is above the programmed range. This usually points to a problem with the idle air control valve, throttle body, or a sensor that tells the computer how fast the engine is spinning.

medium ⏱️ 30‑60 minutes ⚠️ Can you still drive? Yes, but expect rough idle, higher fuel use, and possible emissions‑test failure.

P0507 means the idle speed is running high. Learn why it happens, how to diagnose it, and the cost to fix it on Toyota, Honda, Ford and Chevrolet.

Diagnostic steps:
  1. Verify obvious issues
  2. Read live data
  3. Test IAC valve operation
  4. ...see all 6 steps →
Read full diagnostic guide →

P0520: P0520 signals a fault in the oil‑pressure sensor or its wiring. The Powertrain Control Module (PCM) isn’t receiving a valid pressure signal, so it may ignore a real‑low‑oil condition or trigger a false warning.

low ⏱️ 30–60 minutes ⚠️ The vehicle can be driven with a P0520 code, but continued operation risks insufficient oil pressure, which can cause severe engine wear or failure.

Step‑by‑step instructions for fixing P0520. Learn what the Engine Oil Pressure Sensor/Switch Circuit Malfunction means, whether you can drive with it, and...

Diagnostic steps:
  1. Step 1 – Visual Inspection
  2. Step 2 – Retrieve Freeze‑Frame Data
  3. Step 3 – Watch Live Sensor Data
  4. ...see all 6 steps →
Read full diagnostic guide →

P0562: P0562 tells the powertrain control module that the overall system voltage is below the required threshold. This usually means the battery isn’t delivering enough voltage or a wiring problem is dropping voltage before it reaches the PCM.

low ⏱️ 30-60 minutes ⚠️ Yes, you can drive, but expect reduced performance and possible stalling until the issue is resolved.

Learn what P0562 means, why your vehicle’s voltage is low, and how to fix it. Get step‑by‑step DIY instructions, cost estimates, and make‑specific tips for...

Diagnostic steps:
  1. Visual Inspection for Loose Connections
  2. Battery Voltage Test
  3. PCM Power Supply Check
  4. ...see all 5 steps →
Read full diagnostic guide →

Understanding Powertrain Speed & Idle Codes

Powertrain Speed & Idle diagnostic trouble codes are set by your vehicle's onboard computer (ECU/PCM) when it detects a problem in the speed & idle system. Here's what you need to know:

  • How codes are triggered: Sensors monitor speed & idle performance. When readings fall outside expected ranges, the ECU stores a DTC and illuminates the check engine light.
  • Freeze frame data: When a code is set, the ECU also records engine conditions at that moment. This data helps pinpoint the exact cause.
  • Pending vs. confirmed: A code becomes "confirmed" after multiple drive cycles with the same fault. Pending codes may clear on their own.

Tools You'll Need for Diagnosis

  • OBD-II scanner — Essential for reading and clearing codes. A basic scanner works for most codes.
  • Digital multimeter — For testing sensor voltages, resistance, and continuity.
  • Repair manual — Vehicle-specific wiring diagrams and specifications.
  • Safety equipment — Gloves, safety glasses, jack stands for under-vehicle work.

When to See a Mechanic

While many speed & idle codes can be diagnosed at home, see a professional if:

  • The code is critical severity — driving may cause further damage
  • Multiple related codes are present — suggests a deeper systemic issue
  • You don't have the tools or experience for the required diagnostic steps
  • The repair involves fuel system, exhaust, or catalytic converter work