OBD Guide
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C1240

ABS Hydraulic Pressure Differential Switch Input Short Circuit To Battery

C1240 is an OBD-II diagnostic trouble code meaning: ABS Hydraulic Pressure Differential Switch Input Short Circuit To Battery. Common causes: damage to the wiring harness to the differential pressure sensor, short circuit in the sensor circuit. Estimated repair cost: $56–278.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–278 (est.)

Symptoms

  • The ABS indicator on the dashboard is on
  • ABS does not activate when braking
  • Possible activation of other related systems (ESP, EBD)
  • Error C1240 saved in logbook

Causes

  • Damage to the wiring harness to the differential pressure sensor
  • Short circuit in the sensor circuit
  • Malfunction of the differential pressure sensor itself
  • Corrosion or oxidation of contacts
  • Problems with the ABS hydraulic unit

How to Fix

  1. Carry out diagnostics with a scanner to confirm the code
  2. Visually inspect the wiring harness and sensor contacts
  3. Check the resistance and voltage in the sensor circuit
  4. If necessary, replace the sensor or repair the wiring harness
  5. Clean or replace corroded contacts
  6. In difficult cases, replace the ABS hydraulic unit

Related codes

C1241C1242C1243U0121

FAQ

What does the C1240 code mean?

C1240 is an OBD-II diagnostic trouble code that indicates: ABS Hydraulic Pressure Differential Switch Input Short Circuit To Battery

What causes a C1240 error code?

The most common causes of C1240 include: Damage to the wiring harness to the differential pressure sensor; Short circuit in the sensor circuit; Malfunction of the differential pressure sensor itself; Corrosion or oxidation of contacts.

How do I fix a C1240 diagnostic trouble code?

To fix C1240: Carry out diagnostics with a scanner to confirm the code. Visually inspect the wiring harness and sensor contacts. Check the resistance and voltage in the sensor circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C1240?

Limited driving only, diagnose soon

How much does it cost to fix C1240?

The estimated repair cost for C1240 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

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