Intermediate Shaft Speed Sensor C Circuit Malfunction
The P2749 code indicates a problem with the intermediate shaft speed sensor 'C' circuit. This sensor monitors the rotational speed of the intermediate shaft within the transmission, providing critical data to the powertrain control module (PCM) for shift timing and torque converter lockup. A fault in this circuit can cause erratic shifting, transmission slippage, or limp mode. Common causes include a faulty sensor, damaged wiring, or a poor electrical connection.
01. Most Common Causes
- Faulty intermediate shaft speed sensor C
- Damaged or corroded wiring/connectors in the sensor circuit
- Low transmission fluid level or contaminated fluid
- Internal transmission mechanical failure
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or erratic shifting
- Transmission slipping or delayed engagement
- Reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and record freeze frame data.
Step 2: Inspect the sensor and wiring for damage, corrosion, or loose connections.
Step 3: Test sensor resistance and voltage supply using a multimeter.
Step 4: Check transmission fluid level and condition; top off or replace if necessary.
Step 5: If all else is normal, replace the intermediate shaft speed sensor C.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the transmission may shift erratically or fail, potentially causing further damage.
How much does it cost to fix?▼
Repair costs typically range from $150 to $300, including parts and labor, depending on the vehicle and shop rates.