C1289 — Pressure Transducer Redundant / Secondary Input Circuit Failure #

Note: The wording of this Diagnostic Trouble Code (DTC) may vary depending on the vehicle manufacturer.
Known description variations:

• Pressure Transducer Circuit Redundancy Fault (Ford)
• Secondary Pressure Sensor Input Circuit Malfunction (Nissan)
• Brake Pressure Sensor 2 Circuit Failure (Toyota)

Summary of the C1289 Code #

The C1289 code indicates a problem with the redundant or secondary input circuit for a pressure transducer, most often related to the brake or hydraulic system. A pressure transducer is an electronic sensor that converts physical pressure into an electrical signal, allowing the vehicle’s control module to monitor real-time pressures (such as brake fluid or hydraulic assist). This code means the OEM (Original Equipment Manufacturer) has detected a discrepancy or fault in the backup or secondary electrical circuit of this sensor. Such redundancy circuits are used for safety, ensuring that if one fails, the other can take over or provide verification. When both signals disagree or one fails, the system sets the C1289 code and may limit certain vehicle functions.

Common Symptoms for C1289 #

Symptoms of a C1289 code can range from subtle to severe. In some cases, the driver may not notice a difference under normal conditions, but in others, the vehicle’s safety systems may be compromised. Expect one or more of the following:

• ABS warning light illuminated (Anti-lock Braking System)
• Brake warning light or similar dashboard indicators
• Loss of ABS, traction control, or stability assist functions
• Stiffer or less responsive brake pedal
• Possible reduction in braking performance
• Stored trouble codes in the ABS or related ECU

Probable Causes for C1289 #

The C1289 code is typically triggered by issues within the sensor circuit itself, but several root causes are possible. Typically, these occur in the following order of likelihood:

1. Faulty pressure transducer (sensor)
2. Damaged or corroded wiring/connectors between the sensor and control module
3. Poor ground connection or intermittent electrical contact
4. Malfunctioning ABS control module (rare, but possible)
5. Hydraulic fluid contamination affecting sensor operation (less common)

Step-by-Step Diagnosis for C1289 #

Diagnosing a C1289 code requires a methodical approach to avoid unnecessary parts replacement. Here’s a typical diagnostic process:

• 1. Scan for all ABS-related codes and note any other accompanying DTCs.
• 2. Visually inspect the pressure sensor and wiring harness for obvious damage, corrosion, or loose connectors.
• 3. Check sensor signal and reference voltages at the connector using a digital multimeter.
• 4. Test wiring continuity between the sensor and the control module for shorts, opens, or high resistance.
• 5. Inspect and clean ground connections related to the ABS circuit.
• 6. Substitute with a known-good sensor if available to verify sensor failure.
• 7. Check for technical service bulletins (TSBs) regarding C1289 for your specific make/model.

Possible Repairs for C1289 #

Once the root cause is identified, repairs become straightforward. The most common fixes for a C1289 code include:

• Replace faulty pressure transducer (sensor) if found defective
• Repair or replace damaged wiring or connectors
• Clean and secure ground points to ensure proper electrical contact
• Replace ABS control module (only if confirmed defective after all other checks)
• Flush and replace contaminated hydraulic fluid if moisture or debris affected sensor operation

Is It Safe to Drive with C1289? #

Driving with a C1289 code is NOT recommended. While you may still have basic braking ability, the vehicle’s ABS and stability control systems are likely disabled. This means you could lose traction control and enhanced stopping capability in emergency or slippery conditions. For your safety and that of others, address this fault as soon as possible and avoid driving in adverse conditions until repairs are completed.

Vehicles Most Commonly Affected by C1289 #

While the C1289 code is used by multiple OEMs, it is most frequently observed in vehicles with advanced braking and stability control systems. Commonly affected models include:

• Ford F-Series (F-150, F-250)
• Nissan Altima, Maxima, Pathfinder
• Toyota Camry, Highlander, Tacoma
• Infiniti G-Series, Q-Series
• Some Mazda and Lexus models with electronic brake distribution

Common Mistakes & Best Practices for C1289 Diagnosis #

Even experienced technicians can fall into traps when diagnosing this code. Here are frequent errors and how to avoid them:

• Assuming the sensor is always at fault—always check wiring and grounds first
• Overlooking corrosion in connectors, especially in areas exposed to road salt or moisture
• Ignoring related codes that may indicate a shared root cause
• Clearing codes before recording freeze-frame data, which can aid diagnosis
• Not verifying repair with a road test and confirming the code does not return

Quick FAQ for C1289 #

Still have questions? Here are some fast answers:

• Q: Can I just clear the code and keep driving?
  A: Clearing the code without fixing the underlying issue will not restore ABS or stability systems and the fault is likely to return.
• Q: How much does it cost to fix C1289?
  A: Repair costs vary. Sensor replacement usually ranges from $100–$300 including parts and labor. Wiring repairs may be less, but module replacement could exceed $500.
• Q: Will C1289 cause my inspection to fail?
  A: Yes, any active ABS or brake warning lights will typically result in a failed state inspection/emissions test.