P2602 — Coolant Pump "A" Control Circuit Low

powertrain (engine/transmission)

Is it safe to drive?

Drive with caution Drive with caution and watch the temperature gauge. A thermostat stuck open mainly costs fuel; any sign of overheating means stop immediately — driving an overheating engine destroys head gaskets and worse.

How to diagnose with an OBD scanner

  1. Read the code and freeze frame Connect an OBD2 scanner, confirm P2602 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
  3. Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the engine cooling and temperature control for damage, corrosion, chafing or poor contact.
  4. Subsystem check Check for supply voltage at the coolant pump "A" control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
  5. Subsystem check Watch coolant temperature in live data during warmup — it should climb smoothly to operating temperature.
  6. Subsystem check Check coolant level and feel upper/lower radiator hoses to verify thermostat operation.
  7. Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2602 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P2602 (parts and labor, USD, independent shop rates): Cooling system repair (pump, fan, radiator): $300–$1,200; Replace the thermostat: $150–$400; Replace the coolant temperature sensor: $100–$300. Overall, fixing P2602 usually costs between $100 and $1,200. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

Is it safe to drive with P2602?

Drive with caution and watch the temperature gauge. A thermostat stuck open mainly costs fuel; any sign of overheating means stop immediately — driving an overheating engine destroys head gaskets and worse.

How do I diagnose P2602 myself?

Start with a scan: confirm P2602, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the coolant pump "A" control, and verify the suspect component against live data before buying parts.

How much does it cost to fix P2602?

Cooling system repair (pump, fan, radiator) — $300–$1,200; Replace the thermostat — $150–$400; Replace the coolant temperature sensor — $100–$300. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

Will P2602 clear itself?

Sometimes P2602 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What is the most common cause of P2602?

The most common causes are: faulty coolant temperature sensor, water pump or radiator issues, thermostat stuck open or closed.

What does P2602 mean?

The engine control module sets P2602 when it detects a fault in the engine cooling and temperature control. In practical terms: coolant pump "A" control circuit low. The code belongs to the powertrain (engine/transmission) group of OBD2 codes.

“Circuit low” means the voltage on the coolant pump "A" control circuit stays below the expected minimum — close to ground. The usual physical reasons are a short to ground, a chafed wire touching metal, a missing supply voltage, or a failed component dragging the signal down.

The module monitors this system continuously while driving. When readings fall outside the expected range for a defined number of drive cycles, it stores P2602 and switches on the warning light. Freeze frame data saved with the code shows the exact conditions — rpm, load, temperature, speed — at the moment the fault was detected, which is the best starting point for diagnosis.

What causes P2602?

  • missing supply voltage to the coolant pump "A" control
  • signal wire shorted to ground (chafed insulation)
  • failed coolant pump "A" control pulling the signal low
  • water pump or radiator issues
  • low coolant level or air in the system
  • wiring faults in the sensor circuit
  • failed cooling fan or fan relay

Common symptoms of P2602

  • increased fuel consumption
  • Check Engine Light on
  • temperature gauge reads low or never reaches normal
  • poor cabin heat
  • cooling fans running constantly
  • overheating warnings in severe cases

How to diagnose P2602

  1. Connect an OBD2 scanner, confirm P2602 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
  3. Visually inspect the wiring harness and connectors related to the engine cooling and temperature control for damage, corrosion, chafing or poor contact.
  4. Check for supply voltage at the coolant pump "A" control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
  5. Watch coolant temperature in live data during warmup — it should climb smoothly to operating temperature.
  6. Check coolant level and feel upper/lower radiator hoses to verify thermostat operation.
  7. Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2602 does not return.

How to fix P2602

Start with the cheapest and most common causes before replacing expensive parts:

  • Cooling system repair (pump, fan, radiator) — $300–$1,200
  • Replace the thermostat — $150–$400
  • Replace the coolant temperature sensor — $100–$300

How much does it cost to fix P2602?

Repair cost depends on which component actually failed. Typical scenarios for P2602 (parts and labor, USD, independent shop rates):

  • Cooling system repair (pump, fan, radiator): $300–$1,200
  • Replace the thermostat: $150–$400
  • Replace the coolant temperature sensor: $100–$300

Overall, fixing P2602 usually costs between $100 and $1,200. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Can you drive with P2602?

Drive with caution and watch the temperature gauge. A thermostat stuck open mainly costs fuel; any sign of overheating means stop immediately — driving an overheating engine destroys head gaskets and worse.

Related OBD2 codes