ECM/PCM Power Input Signal Low
The P2507 code indicates that the Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected a low voltage condition on its main power supply circuit. This typically means the voltage at the ECM/PCM is below the required threshold (often below 9-10 volts). The ECM/PCM relies on a stable power supply to operate sensors, actuators, and communication networks. A low input signal can cause erratic engine behavior, poor performance, and may prevent the vehicle from starting. Common causes include a weak battery, faulty alternator, corroded or loose battery terminals, damaged wiring or connectors in the power supply circuit, or a failing ECM/PCM itself.
01. Most Common Causes
- Weak or discharged battery
- Faulty alternator not charging properly
- Corroded or loose battery terminals or cables
- Damaged wiring or connectors in the ECM/PCM power supply circuit
- Failing ECM/PCM
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine cranks slowly or fails to start
- Engine stalling or rough idle
- Dimming lights or electrical issues
- Reduced engine performance or power loss
03. Step-by-Step Diagnosis
Step 1: Use a multimeter to check battery voltage (should be 12.6V+ engine off, 13.5-14.5V engine running).
Step 2: Inspect battery terminals and cables for corrosion, looseness, or damage; clean and tighten as needed.
Step 3: Check alternator output; if low, test alternator and replace if faulty.
Step 4: Inspect wiring and connectors from battery to ECM/PCM for breaks, shorts, or poor connections; repair as necessary.
Step 5: If all else is fine, test ECM/PCM power and ground circuits; consider ECM/PCM replacement if internal fault is suspected.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Low power to the ECM/PCM can cause stalling, poor performance, or sudden loss of power, which may be dangerous. Have the vehicle diagnosed and repaired promptly.
How much does it cost to fix?▼
The cost varies depending on the cause. Simple fixes like cleaning terminals or replacing a battery can cost $50-$150. Alternator replacement may run $200-$500. ECM replacement can exceed $500-$1000. Diagnosis is typically $100-$150.