P2602 Code: Coolant Pump A Control Circuit Low

What Does the P2602 Code Mean?

P2602 is the diagnostic label for Coolant Pump “A” Control Circuit Low. Ford and Volkswagen diagnostic materials use P2602 for coolant pump A control circuit low, while the controlled pump and thresholds differ by application. It is a monitor result, not a parts order, and it does not by itself prove that coolant flow is low, that pump A is mechanically seized, or that the engine is overheating.

The output may be relay-switched, pulse-width controlled, low-side driven, high-side driven, or managed by smart pump electronics. The useful distinction is between an electrical circuit-low fault, a pump that is commanded but cannot move coolant, and a separate cooling-system performance or overheating problem. That distinction determines whether the next test belongs at a connector, a power or ground path, a control signal, a hydraulic or mechanical system, or an operating-condition check.

A short to ground, missing feed, high-resistance connection, failed pump electronics, driver protection, or shared supply fault can all create low-circuit evidence. A scan tool can preserve operating context and compare related data, but it cannot replace a current wiring diagram, connector view, service precautions, and any specified breakout leads or measurement method. Do not import pin numbers, thresholds, or component locations from another model year.

P2602 Symptoms, Severity, and Driving Safety

P2602 ranges from a prompt electrical repair to an immediate thermal-safety concern. The code alone does not prove overheating, but loss of a required pump can quickly affect an engine, turbocharger, battery, inverter or cabin-heater loop.

P2602 Causes and the Evidence That Separates Them

The strongest P2602 diagnosis explains the code definition, the captured operating conditions, and any companion codes with one testable fault path. The physical pump and loop must be identified before any fuse, connector or temperature conclusion is useful.

Cause lists are starting points. If a fuse opened, find the overcurrent source and every load on that fuse before restoring power. Test the circuit in its failed state when possible, document the result, and replace a part only after the measured evidence points to it.

Using UR1000 to Organize P2602 Evidence

The iCARZONE UR1000 Bidirectional Scan Tool with ECU Coding supports full-system diagnostics, available DTCs, freeze frame, ECU information and live data. For P2602, use those records to compare pump command, speed or feedback with loop temperatures, fan command, system voltage and related module faults, while keeping the first-failure order intact.

The official product page advertises bidirectional control and ECU coding. Coverage varies by VIN, ECU and software. Do not assume a menu item can command coolant pump A; active tests and parameter names are vehicle-specific, and a supported command is not proof that the connected component can physically respond.

Work cold and depressurized. Smart pumps can start automatically. Use approved backprobes, fused test leads and load methods; never bypass a controller output. Treat orange cables and high-voltage cooling components as restricted unless qualified.

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How to Diagnose P2602 in 6 Evidence-Based Steps

Use this order to avoid erasing the event or chasing a plausible part without proof. Start with loop identity because several vehicles have multiple electrically driven coolant pumps. A failed test should lead to the next branch in the OEM procedure; a passed test should narrow the search rather than trigger replacement.

P2602 Quick Diagnostic Path

• 1

  Make the System Safe and Save Data

  • Stop for thermal or high-voltage warnings; allow cooling and record every module.
  • Capture temperatures, pump command/feedback, voltage, fan state and first-failure order.
• 2

  Identify Pump A and Its Loop

  • Use the VIN service information to locate the exact pump, controller and coolant circuit.
  • Confirm high-voltage restrictions, automatic-start behavior, fuse/relay and shared paths.
• 3

  Inspect Cold External Hardware

  • With the system safe, inspect coolant leaks, connector seals, routing, corrosion and grounds.
  • Do not open the system or reach near automatic fans while hot.
• 4

  Load-Test Power and Ground

  • Command the pump only if supported and safe, then measure supply and ground voltage drop.
  • A static 12-volt reading without load does not prove the circuit can carry current.
• 5

  Test Control and Pump Load

  • Follow the specified control-signal, current or communication test and isolate the pump as directed.
  • Do not jumper a smart pump or controller output unless the OEM procedure supplies a protected method.
• 6

  Repair and Verify Thermal Response

  • Correct the proven circuit, pump or supply fault, then refill and bleed by specification if opened.
  • Confirm command/feedback, temperature response, fan strategy and monitor completion without return.

How to Fix P2602 and Verify the Repair

A completed repair should correct the proven fault and preserve the original evidence in the work record. Verify normal loaded voltage, pump command/feedback, leak-free coolant level, correct bleed, expected temperature change and no returning thermal or circuit faults.

Clear codes only after the repair and baseline checks are complete. Run the specified monitor or road-test conditions, rescan every relevant module, and compare the post-repair data with the saved event. A code that does not return during a short idle period is not automatically a verified fix.

P2602 OEM Differences and DIY Limits

Pump A may serve the engine, turbocharger, inverter, battery, charge-air cooler or another thermal circuit depending on the vehicle. That is why the displayed OEM description, wiring diagram, component locator, terminal identification, test conditions, and service bulletin applicability must match the full VIN.

Some pumps use simple motor control; others contain electronics and communicate with a controller. Generic guidance can organize evidence, but it must stop before unverified terminal probing, module programming, high-energy work, or disassembly that requires special tools and cleanliness controls.

Related Thermal, Voltage, and Sensor Guides

Companion codes can change the test order for P2602. Review these verified iCARZONE guides for nearby monitor families, but use the exact vehicle service information to decide whether they share a feed, ground, sensor, controller, or physical system.

For other stored faults, use the iCARZONE OBD-II fault-code center.

Frequently Asked Questions About P2602

Sources and Technical Review Notes

• Volkswagen Touareg Quick Reference Specification Book — Lists P2600 open, P2602 circuit low and P2603 circuit high for coolant pump A; application thresholds remain specific.
• Ford Diagnostic Code Table in NHTSA Record — Lists P2602 as Coolant Pump A Control Circuit Low, supporting the electrical direction.

iCARZONE

Technical sources checked September 3, 2026. This is a source-based diagnostic guide, not a report of a hands-on vehicle repair. Confirm pump and loop identity, control design, high-voltage boundary, loaded tests, coolant and bleed procedure for the exact VIN.