P1486 Cooling Fan Secondary Circuit Low Performance
The P1486 code indicates that the Powertrain Control Module (PCM) has detected a low performance condition in the secondary cooling fan circuit when the high-speed fan is commanded on. In Chrysler/Dodge/Jeep vehicles, the cooling fan system uses a two-speed circuit: the primary circuit controls low speed and the secondary circuit controls high speed. The PCM monitors the secondary fan relay status and detects that, although high-speed fan activation has been commanded, the secondary circuit is not operating correctly or has abnormally low resistance/current. This condition can lead to engine overheating if not corrected, as high-speed airflow is essential for maintaining coolant temperature under high thermal load conditions.
01. Most Common Causes
- Faulty or damaged secondary fan relay
- Short to ground or open circuit in the secondary fan wiring
- Corroded, loose, or damaged relay connector or terminals
- Cooling fan motor with high internal resistance or mechanical failure
- Blown or incorrect amperage fuse in the secondary fan circuit
- Internal PCM failure (less common but possible)
02. Symptoms You Will Notice
- Engine overheating, especially in stop-and-go traffic or at idle
- Check Engine Light illuminated
- High-speed cooling fan not operating when A/C is on or engine is hot
- Reduced air conditioning performance
03. Step-by-Step Diagnosis
Scan for codes and verify P1486 is present; check for related codes
Inspect the secondary fan relay and its connector for corrosion, damage, or loose pins
Test the relay by swapping with a known good relay or using a multimeter to check coil resistance and continuity
Check the secondary fan fuse and replace if blown; verify correct amperage rating
Measure voltage and ground at the fan motor connector with the relay commanded on; if no voltage, trace wiring for opens/shorts
Test the fan motor by applying direct battery power and ground; if it doesn't run or runs slowly, replace the motor
If all components check out, suspect a PCM fault; perform a PCM relay output test or consult a professional
1. Frequently Asked Questions
Is it safe to drive?▼
Driving with this code is not recommended, especially in hot weather or heavy traffic, as the high-speed fan may not engage, leading to engine overheating and potential damage. Have the issue diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs typically range from $100 to $400, depending on the cause. A relay or fuse replacement is on the lower end, while a fan motor or wiring repair can be higher. PCM replacement, if needed, can exceed $500.