P118B Cadillac Code - Particulate Matter Sensor Temperature Not Plausible
Quick Answer
The particulate matter (PM) sensor monitors the amount of the particulates (soot) in the diesel exhaust gas exiting the tailpipe. Common causes include Faulty Exhaust Particulate Matter Sensor, Exhaust Particulate Matter Sensor harness is open or shorted, Exhaust Particulate Matter Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P118B Cadillac indicates Particulate Matter Sensor Temperature Not Plausible.
- Common causes
- Common causes include Faulty Exhaust Particulate Matter Sensor, Exhaust Particulate Matter Sensor harness is open or shorted, Exhaust Particulate Matter Sensor circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P118B Cadillac Description
The operation of the PM Sensor is based on the electrical conductivity characteristic of the diesel particulate. As the exhaust gas flows over the sensing element, soot is absorbed in the combs between the electrodes, eventually creating a conductive path. When the path is formed, it generates a current based on the voltage being applied to the element. The measurement process continues until a preset current value is reached. To avoid misleading readings, the sensor performs a regeneration where the soot is cleaned off by heating up the element, before the measurement phase begins. The amount of regenerations is based on vehicle strategy; when the calibrated number of regenerations is reached, the cumulative current readings are used to determine the amount of soot concentration in the exhaust gas which in turn determines the collection efficiency of the diesel particulate filter (DPF).
What are the Possible Causes of the DTC P118B Cadillac?
- Faulty Exhaust Particulate Matter Sensor
- Exhaust Particulate Matter Sensor harness is open or shorted
- Exhaust Particulate Matter Sensor circuit poor electrical connection
How to Fix the DTC P118B Cadillac?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P118B Cadillac code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P118B Cadillac Code
What does the OBDII code P118B mean on a Cadillac?
The code P118B on a Cadillac refers to "Particulate Matter Sensor Temperature Not Plausible," indicating an issue with the particulate matter (PM) sensor's temperature reading.
What are the common symptoms of code P118B?
Symptoms may include a check engine light, reduced engine performance, poor fuel efficiency, or an active diesel particulate filter (DPF) regeneration issue.
What causes the P118B code to appear?
Common causes include a faulty particulate matter sensor, wiring issues, a malfunctioning engine control module (ECM), or an inaccurate temperature reading from the sensor.
Can a dirty diesel particulate filter cause the P118B code?
While a dirty DPF itself may not directly cause this code, it could contribute to sensor issues if it leads to overheating or abnormal exhaust flow.
How do I diagnose the P118B code?
Diagnosis involves checking the PM sensor and its wiring for damage, testing the sensor's temperature output with a scan tool, and verifying the ECM's functionality.
Can I drive my Cadillac with the P118B code?
Driving with this code is not recommended, as it may lead to further damage to the exhaust system or reduced engine performance.
How is the P118B code fixed?
Repairs may include replacing the particulate matter sensor, repairing damaged wiring, or reprogramming/updating the ECM if necessary.
Is the particulate matter sensor expensive to replace?
The cost of replacing a PM sensor can vary, typically ranging from $200 to $600, depending on the vehicle model and labor costs.
Can a software update fix the P118B code?
In some cases, an ECM software update can resolve the issue if it stems from incorrect temperature calibration or a known software bug.
What tools are needed to troubleshoot the P118B code?
A diagnostic scan tool, a multimeter for testing wiring, and repair manuals specific to your Cadillac model are commonly needed for troubleshooting.
Discuss the causes and fixes for P118B Cadillac OBDII Code
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