P0592 — Cruise Control Multi-Function Input "B" Circuit Low

OBD2 code P0592 flags a problem with the sensor and actuator circuits (cruise control multi-function input "B" circuit low). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, faulty sensor or actuator of the affected circuit, control module driver fault.

powertrain (engine/transmission)

Is it safe to drive?

Caution - cruise control impaired P0592 normally affects speed-control operation rather than basic acceleration or braking. The vehicle can usually be driven without cruise control, but the fault should be corrected before relying on that feature. If P0592 is accompanied by brake, ABS, steering, or charging-system warnings, stop safely and diagnose those conditions promptly.

Typical symptoms

  • P0592 is stored in the powertrain control module and may appear as a pending or confirmed trouble code.
  • Cruise control may be completely unavailable or unable to engage.
  • The SET, COAST, or RESUME commands may not operate normally.
  • Cruise control may cancel immediately after an engagement attempt.
  • Engine operation and normal braking will usually remain unaffected when P0592 is the only stored code.

Common causes

  • P0592 is commonly caused by a short to ground in the cruise-control multi-function input B circuit.
  • A stuck or internally shorted contact in the cruise-control multi-function switch can hold input B at a low voltage.
  • Corroded, damaged, or water-contaminated connectors may allow the input B wire to leak current to ground.
  • Steering-column wiring, including any clock-spring wiring path, may be chafed or pinched.
  • Low charging-system voltage, an unstable PCM ground, or an incorrect input reference voltage can cause P0592 to be stored.
  • A failed PCM input driver is possible, but the wiring and multi-function switch should be tested first.

How to diagnose with an OBD scanner

  1. Confirm P0592 with an OBD scanner Connect an OBD scanner such as ELM327 or AIScanAuto and read stored, pending, and freeze-frame data. Confirm that P0592 is present and note any related cruise-control, ABS, or voltage codes before disconnecting the battery.
  2. Inspect the input wiring and connectors Examine the cruise-control multi-function switch connector, steering-column harness, and PCM connector for corrosion, water intrusion, bent terminals, chafing, or pin damage. Repair damaged terminals and seals before testing the circuit electrically.
  3. Check power, grounds, and input B voltage Verify that the battery is fully charged and all relevant control-module grounds are clean and secure. Using the vehicle wiring diagram, back-probe input B at the switch and PCM while operating the cruise switches. The voltage should change as required and match the manufacturer-specified logic; a constant low reading indicates a short or defective switch.
  4. Isolate the multi-function switch If the wiring checks normal, test the cruise-control multi-function switch for a low-resistance or grounded B output. Disconnect it only as directed by the service procedure, since some designs use bias resistors that an open connector could incorrectly imitate as a fault.
  5. Repair and verify the fault Repair the shorted wiring, connector, ground, or faulty switch responsible for P0592. Clear the code with the scanner, confirm that P0592 does not return, and road-test the cruise-control set, cancel, and resume functions.

Approximate repair cost

A typical independent-shop estimate for diagnosing and repairing P0592 is approximately USD 150-600, depending on whether the cause is a switch, a wiring or connector repair, or a control-module input. Figures are estimates and vary by region, labor rates, and parts availability.

Common questions

What does P0592 specifically mean?

P0592 means the PCM detected a low-voltage condition on the cruise-control multi-function input B circuit, usually involving the switch, wiring, connector, ground, or PCM input.

Can I continue driving with P0592 stored?

Yes, normal driving is generally possible with P0592 because the code primarily disables cruise control, but avoid using the failed cruise function until the electrical fault has been repaired.

Should the PCM be replaced for P0592?

No. Replacing the PCM is rarely the first repair for P0592. Inspect and voltage-test the input B wiring and multi-function switch first, with a defective PCM input considered only after those checks pass.

Why does P0592 sometimes return after the code is cleared?

P0592 can return when an intermittent short, high-resistance connection, damaged harness section, or defective switch contact appears again while the vehicle is operating. Confirming the code under the same driving conditions is essential.

When your scan tool pulls code P0592, the engine computer is telling you it has detected a problem with the cruise control multi-function input "B" circuit — specifically, the voltage on that circuit has dropped below acceptable levels and is sitting near ground potential. This falls under the powertrain category in the OBD2 standard, which covers engine and transmission-related faults. The underlying issue is almost always a short to ground somewhere in the wiring, a chafed conductor making contact with metal, a broken supply voltage, or a component that has failed in a way that drags the signal low.

The engine control module (ECM) or powertrain control module (PCM) does not trigger P0592 based on a single bad reading. It watches the cruise control circuit through multiple drive cycles and only activates the check engine light once the fault condition repeats under the specific circumstances the manufacturer defines. This is why the freeze frame data stored alongside P0592 is so valuable — it captures engine load, RPM, coolant temperature, and vehicle speed at the exact moment the problem occurred. Use those numbers as a target when you recreate the failure condition during testing.

Symptoms of P0592

When P0592 is active, you may notice one or more of the following:

  • The cruise control system stops working entirely or operates only intermittently
  • Fuel economy drops because the engine management system falls back to a less efficient operating mode
  • Reduced performance or limp-home mode depending on which component is affected
  • The check engine light remains illuminated on the dashboard
  • Other cruise-related functions, such as set speed memory, may become unresponsive

Common Causes of P0592

Several conditions can pull the cruise control multi-function input "B" circuit low. The most probable culprits, listed from most to least likely:

  1. Missing supply voltage — The circuit is not receiving the power it needs to operate properly
  2. Failed cruise control multi-function input "B" component pulling the signal down to ground
  3. Signal wire shorted to ground from damaged or chafed insulation
  4. Corroded, loose, or physically damaged connector interrupting current flow
  5. Faulty sensor or actuator within the affected circuit
  6. Blown fuse protecting the cruise control circuit
  7. Poor ground connection preventing proper circuit function

How to Diagnose P0592

Follow these steps to isolate the root cause of P0592 without replacing parts you do not need:

  1. Connect an OBD2 scanner, confirm P0592 is stored, and record the freeze frame data — these conditions show exactly when and where the fault happened.
  2. Scan for related diagnostic trouble codes. Secondary codes often point directly to the failed circuit. While you are at it, search for technical service bulletins (TSB) for your specific make and model on the manufacturer website or nhtsa.gov — many P0xxx codes have published factory fixes or software updates.
  3. Perform a thorough visual inspection of the wiring harness and connectors associated with the cruise control multi-function input "B." Look for damaged insulation, corroded terminals, broken lock tabs, and any sign of wires rubbing against metal.
  4. Test for supply voltage at the connector first. Then measure resistance from the signal wire to ground — a reading near zero ohms confirms a short to ground in the harness.
  5. At the component connector, verify reference voltage, ground integrity, and signal continuity one by one.
  6. Conduct a wiggle test on the harness while monitoring live data. Any signal dropouts expose broken conductors inside the insulation.
  7. Clear the code, complete a full drive cycle including the conditions captured in the freeze frame, and verify that P0592 does not return.

Repair Options and Costs for P0592

Address the cheapest and most common causes before spending money on major components:

  • Wiring or connector repair: $80–$250
  • Replace faulty sensor or actuator: $150–$500
  • Control module repair: $300–$1,000

Total Repair Cost for P0592

Your actual out-of-pocket expense depends entirely on what component is faulty. At independent shop rates, a typical P0592 repair breaks down as follows:

Repair Scenario Parts Labor Total
Wiring or connector fix $20–$100 $60–$150 $80–$250
Sensor or actuator replacement $80–$350 $70–$150 $150–$500
Control module repair $200–$700 $100–$300 $300–$1,000

Most P0592 cases fall between $80 and $1,000 depending on which part fails. Spending time on a solid diagnosis before purchasing components is the smartest move — the most expensive repair is rarely where you should start.

Can You Drive with P0592?

The vehicle remains drivable in most situations, though you may experience reduced performance, a disabled cruise control system, or slightly higher fuel consumption. Treat the issue as urgent if you notice stalling, failure to start, or warnings related to the brakes or steering — those symptoms indicate a more serious condition that demands immediate attention.

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