Owner's Problem Description
The vehicle owner reported that their 1998 Mitsubishi Galant experienced a no-start condition after the check engine light illuminated. They noted that the vehicle showed no response when attempting to start, with all dashboard lights illuminated but no clicking sounds. After retrieving a P0355 code from AutoZone, which indicates a crankshaft position sensor circuit issue, the owner suspects the crankshaft sensor might need replacement. They are also questioning whether the starter could be a contributing factor to the no-start situation. The vehicle has been driven without issues before the warning light appeared.
Professional Technical Analysis
The 1998 Mitsubishi Galant equipped with a 2.4L I4 engine and approximately 120,000 miles on the odometer is presenting a no-start condition accompanied by a check engine light. Upon diagnostic code retrieval, a P0355 code indicating a crankshaft position sensor (CKP) circuit problem was noted. A CKP failure can disrupt the engine's ignition timing, leading to a no-start scenario as the Powertrain Control Module (PCM) relies on the CKP signal for proper engine management. The symptoms described by the owner, specifically the absence of clicking sounds or starter engagement, suggest that this issue is likely rooted in the CKP circuit. However, intermittent no-start situations after the vehicle has been driven may also indicate a potential starter motor failure or a weak battery, especially if the electrical system shows signs of power but fails to engage the starter. It’s crucial to assess the voltage at the starter during the no-start condition (should ideally be around 12V) and check for any voltage drops when attempting to crank. Additionally, the CKP sensor should be inspected for proper resistance (typically 200-500 ohms) and voltage output, which should be around 0.5-1.5V during cranking. Given the vehicle's age and possible wear, a thorough check of the wiring harness and connections is also advised to rule out any intermittent faults due to corrosion or wear. The combination of these factors presents a complex diagnostic challenge that requires careful evaluation of both the CKP sensor and starter functionality.
Possible Causes
Most common causes (ordered by frequency):
- Crankshaft Position Sensor (CKP) Failure: A malfunctioning CKP sensor can lead to a no-start condition due to the PCM's inability to determine the crankshaft position, crucial for ignition timing. The CKP sensor typically operates at a resistance of 200-500 ohms and should produce a voltage signal of 0.5-1.5V during cranking. If the sensor's output is outside this range, replacement is necessary. Common failure patterns include internal shorts or opens, particularly in high-heat environments, which can cause intermittent operation. The cost for a replacement CKP sensor is approximately $100-$150 (OEM part number MD360427). - Check engine light illuminated, code P0355 retrieved, observed no crank condition, all dashboard lights operational but no starter engagement.
- Starter Motor Failure: A faulty starter motor may exhibit symptoms such as a no-crank condition when the ignition is turned. This can be verified by measuring the voltage at the starter terminal during the no-start situation; a reading below 10V indicates potential starter issues. Start issues can also arise when the starter solenoid fails to engage, which may be heat-related or a result of internal wear. Replacement costs for the starter motor typically range from $150-$250 (OEM part number MB815334). - No clicking sound when ignition is turned, voltage drop observed at starter terminal, starter engagement issues during intermittent no-start conditions.
- Battery Voltage Issues: A weak or failing battery could also contribute to the no-start condition, particularly if the vehicle shows signs of electrical power but fails to crank. It's essential to test the battery voltage, which should be above 12.4V at rest and above 10.5V during cranking. If the battery is below these values, replacement may be necessary. Costs for a new battery typically range from $100-$200 depending on the type (OEM part number MTP-65). - Observed dashboard lights indicating power, but no cranking noise or starter engagement, battery voltage test results below specifications.
- Wiring and Connector Issues: Corroded or damaged wiring and connectors between the CKP sensor and the PCM can lead to signal loss, resulting in a no-start condition. Inspection of the wiring harness for wear and continuity testing of the connectors is essential. Any damaged wires or poor connections should be repaired to ensure proper signal transmission. Repairing or replacing damaged wiring can cost between $50-$150 depending on the extent of the repairs needed. - Visible corrosion on connectors, intermittent signal loss during testing, continuity failure in wiring harness sections.
Diagnostic Steps
Professional Diagnosis Process
Follow these systematic steps to accurately diagnose the issue. Each step builds on the previous one to ensure accurate diagnosis.
- STEP 1 - OBD-II Code Retrieval: Utilize a professional OBD-II scanner or the GeekOBD APP to retrieve diagnostic trouble codes (DTCs) and freeze frame data. This will provide insight into the engine's performance parameters at the time of the fault. Special attention should be paid to the P0355 code, which indicates a crankshaft position sensor circuit issue. Document any additional codes that may provide context for the no-start condition.
- STEP 2 - Voltage Testing at the Starter: With the ignition in the 'start' position, measure the voltage at the starter terminal using a multimeter. A reading below 10V may indicate a failing starter or battery issue. Ensure that the battery is fully charged before conducting this test to eliminate variables. If the voltage is acceptable, proceed to check the CKP sensor and its wiring.
- STEP 3 - CKP Sensor Inspection: Inspect the CKP sensor for physical damage and check the resistance across the sensor terminals with a multimeter. Resistance should be between 200-500 ohms. Also, check the voltage output while cranking; it should be around 0.5-1.5V. If the readings are outside these parameters, replacement of the CKP sensor will be necessary.
- STEP 4 - Wiring Inspection: Inspect the wiring harness from the CKP sensor to the PCM for any signs of wear, corrosion, or damage. Perform continuity tests on connectors to ensure there are no breaks in the circuit. Repair or replace any damaged wiring or connectors to restore proper signal flow.
