Introduction:
Diagnostic Trouble Code (DTC) P1873 indicates a problem within the Torque Converter Clutch (TCC) stator temperature switch circuit. This circuit is crucial for monitoring the temperature within the transmission and preventing damage from overheating. When this code is triggered, it signifies that the Powertrain Control Module (PCM) has detected a low voltage condition in the TCC stator temperature switch circuit, potentially leading to impaired transmission performance and long-term damage.
Comprehensive Table: P1873 - TCC Stator Temp. Switch Circuit Low
| Aspect | Description | Potential Causes |
|---|---|---|
| Definition | TCC Stator Temp. Switch Circuit Low. This indicates the PCM has detected a lower-than-expected voltage in the circuit related to the temperature switch located in the transmission stator. | Short to ground in the wiring; Open circuit in the wiring; Faulty TCC stator temperature switch; Corroded or damaged connector(s); PCM failure (rare); Low transmission fluid level leading to overheating; Internal transmission damage causing excessive heat. |
| Symptoms | Check Engine Light (CEL) illuminated; Possible harsh or erratic shifting; Reduced fuel economy; Transmission overheating; Torque converter clutch not engaging or disengaging properly; Transmission slipping; Stalling at low speeds; Transmission may enter limp mode; No noticeable symptoms. | Failure of TCC to engage; Overheating of the transmission; Damaged transmission components due to overheating; Decreased vehicle performance; Increased wear and tear on transmission. |
| Diagnostic Steps | Visual inspection of wiring and connectors; Check transmission fluid level and condition; Use a multimeter to test the TCC stator temperature switch for continuity and resistance; Inspect the wiring harness for shorts to ground or open circuits; Scan the PCM for other related DTCs; Use a scan tool to monitor the TCC stator temperature sensor data; Perform a wiggle test on the wiring harness to see if the code reappears; Consult the vehicle's service manual for specific diagnostic procedures. | Use of improper diagnostic procedures; Incorrect interpretation of scan tool data; Replacing parts unnecessarily; Ignoring other related DTCs; Failure to properly inspect the wiring harness. |
| Related DTCs | P0740 (Torque Converter Clutch Circuit Malfunction); P0741 (Torque Converter Clutch Circuit Performance or Stuck Off); P0742 (Torque Converter Clutch Circuit Stuck On); P0743 (Torque Converter Clutch Circuit Electrical); P0744 (Torque Converter Clutch Circuit Intermittent); Other transmission-related codes (P0700 series). | Triggering of multiple transmission-related codes; Intermittent TCC operation; Complete failure of the TCC system; Transmission overheating leading to further component damage. |
| Component Locations | TCC Stator Temperature Switch: Located inside the transmission, typically mounted near or on the stator of the torque converter. Wiring Harness: Runs from the transmission to the PCM, usually routed along the chassis or engine bay. Connectors: Located at the TCC stator temperature switch, the PCM, and potentially at intermediate points along the wiring harness. PCM: Typically located under the dashboard or in the engine bay. | Difficulty accessing the TCC stator temperature switch; Damage to the wiring harness during repairs; Corrosion of connectors due to exposure to the elements; Improper PCM location leading to damage. |
| Voltage and Resistance Values | TCC Stator Temperature Switch: Specific voltage and resistance values will vary depending on the vehicle make and model. Consult the vehicle's service manual or a reliable online database for accurate specifications. Typically, a "low" voltage condition will be significantly below the expected range (e.g., below 0.5V when a 5V signal is expected). Resistance values will vary depending on temperature. | Inaccurate voltage and resistance readings due to faulty testing equipment; Incorrect interpretation of voltage and resistance values; Damage to the TCC stator temperature switch during testing; Use of incorrect specifications. |
| Repair Strategies | Repair or replace damaged wiring; Clean or replace corroded connectors; Replace the faulty TCC stator temperature switch; Reflash or replace the PCM (rare); Check and correct transmission fluid level; Repair internal transmission damage (if present); Consult a qualified mechanic for diagnosis and repair. | Ineffective repairs if the root cause is not identified; Damage to other components during repairs; Incorrect installation of replacement parts; Failure to properly diagnose internal transmission damage. |
| Tools Required | Multimeter; Scan tool; Wiring diagram; Socket set; Wrench set; Screwdriver set; Wire stripper; Wire crimper; Electrical tape; Connector cleaner; Vehicle service manual. | Damage to components due to improper tool usage; Inaccurate readings due to faulty testing equipment; Incomplete repairs due to lack of necessary tools; Injury due to improper tool handling. |
| Safety Precautions | Disconnect the negative battery cable before working on electrical components; Use caution when working around hot engine components; Wear safety glasses to protect your eyes; Use proper lifting techniques to avoid injury; Consult the vehicle's service manual for specific safety precautions. | Electrical shock; Burns from hot engine components; Eye injury from flying debris; Back injury from improper lifting; Damage to vehicle components due to improper handling. |
Detailed Explanations:
Definition:
The P1873 DTC specifically points to a low voltage condition detected by the PCM within the circuit responsible for monitoring the TCC stator temperature. The stator is a stationary component within the torque converter, and its temperature is an important indicator of the transmission's overall health. A low voltage signal suggests a problem in the circuit preventing proper communication between the temperature switch and the PCM.
Symptoms:
While the Check Engine Light is the most consistent symptom, other indicators can include erratic shifting, reduced fuel economy, transmission overheating, and issues with the torque converter clutch engagement. In some cases, the transmission might enter a "limp mode" to protect itself from further damage, limiting speed and gear selection. Conversely, some vehicles might exhibit no noticeable symptoms despite the code being present.
Diagnostic Steps:
Begin with a thorough visual inspection of the wiring and connectors associated with the TCC stator temperature switch. Check for any signs of damage, corrosion, or loose connections. Use a multimeter to test the switch for continuity and resistance, comparing the readings to the manufacturer's specifications. A scan tool can be used to monitor the temperature sensor data and identify any anomalies. Performing a "wiggle test" on the wiring harness while monitoring the scan tool data can help pinpoint intermittent issues.
Related DTCs:
The P1873 code is often accompanied by other transmission-related DTCs, particularly those in the P0700 series, which relate to the torque converter clutch circuit. These codes can provide additional clues about the nature of the problem and help narrow down the potential causes. Addressing all related DTCs is crucial for a successful repair.
Component Locations:
The TCC stator temperature switch is located inside the transmission, typically mounted near or on the stator of the torque converter. The wiring harness runs from the transmission to the PCM, often routed along the chassis or engine bay. Connectors are located at the switch, the PCM, and potentially at intermediate points along the harness. The PCM's location varies depending on the vehicle make and model.
Voltage and Resistance Values:
Specific voltage and resistance values for the TCC stator temperature switch will vary depending on the vehicle. Consult the vehicle's service manual or a reliable online database for accurate specifications. The "low" voltage condition indicated by the P1873 code will be significantly below the expected range. Resistance values will also change with temperature, so it's important to consider the ambient temperature when testing the switch.
Repair Strategies:
Repairing the P1873 code often involves repairing or replacing damaged wiring, cleaning or replacing corroded connectors, or replacing the faulty TCC stator temperature switch. In rare cases, a PCM reflash or replacement might be necessary. It's also important to check and correct the transmission fluid level and address any internal transmission damage.
Tools Required:
A multimeter is essential for testing the switch and wiring. A scan tool is needed to read DTCs and monitor sensor data. Other useful tools include a wiring diagram, socket set, wrench set, screwdriver set, wire stripper, wire crimper, electrical tape, connector cleaner, and the vehicle service manual.
Safety Precautions:
Always disconnect the negative battery cable before working on electrical components. Use caution when working around hot engine components. Wear safety glasses to protect your eyes. Use proper lifting techniques to avoid injury. Consult the vehicle's service manual for specific safety precautions.
Frequently Asked Questions:
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What does the P1873 code mean? It indicates a low voltage condition in the TCC stator temperature switch circuit. This means the PCM isn't receiving the expected signal from the switch.
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Can I drive with a P1873 code? It's not recommended, as it could lead to transmission overheating and damage. Get it diagnosed and repaired as soon as possible.
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What are the common causes of the P1873 code? Common causes include wiring issues, a faulty TCC stator temperature switch, or a bad connection. Rarely, the PCM itself is the problem.
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How do I fix the P1873 code? Diagnosis involves checking the wiring, switch, and connections. Repair might involve replacing the switch or repairing the wiring.
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Will replacing the TCC stator temperature switch always fix the problem? Not necessarily. It's crucial to diagnose the root cause before replacing any parts to ensure the correct repair.
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Is this a difficult repair? It depends on your mechanical skills and the complexity of the wiring. If you're not comfortable with electrical work, consult a professional.
Conclusion:
The P1873 DTC signifies a potential issue within the TCC stator temperature switch circuit, which can lead to transmission overheating and damage if left unaddressed. Proper diagnosis, using the right tools and procedures, is essential for identifying and resolving the root cause of the problem and preventing further complications.