What Does P2602 Mean?
The PCM has detected abnormally low voltage in the coolant pump control circuit. This indicates insufficient voltage reaching the pump or a short to ground in the control circuit.
Common Causes
30%
Short to ground in coolant pump control circuit wiring
25%
Failed electric coolant pump with internal short circuit
20%
Damaged or corroded pump connector causing resistance or grounding
15%
Faulty PCM coolant pump driver circuit
10%
Blown fuse or damaged fusible link in pump power circuit
Diagnostic Steps
1
Step 1: Inspect coolant pump connector and wiring for visible damage, corrosion, or chafing against sharp edges
2
Step 2: Disconnect coolant pump connector and measure resistance between control wire and ground (should be open circuit)
3
Step 3: Check for voltage at pump connector with pump commanded on; compare to battery voltage
4
Step 4: Perform insulation resistance test on control circuit wiring from PCM to pump connector
5
Step 5: If wiring tests good, replace coolant pump; if problem persists, test/replace PCM
Estimated Repair Cost
$150 - $700
Parts + labor, varies by vehicle and location
The PCM has detected abnormally low voltage in the coolant pump control circuit. This indicates insufficient voltage reaching the pump or a short to ground in the control circuit.
The most common cause of P2602 (Coolant Pump "A" Control Circuit Low) is: Short to ground in coolant pump control circuit wiring
Typical repair costs for P2602 range from $150 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Coolant pump may not operate at all, leading to rapid engine overheating. Do not drive until repaired if coolant temperature rises abnormally.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2602 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Cooling System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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