P118B on Opel
Particulate Matter (PM) Sensor Temperature Not Plausible
P118B on Opel vehicles indicates particulate matter (pm) sensor temperature not plausible. Au7o has documented this code across 1 Opel model — most commonly on Zafira. P118B is a GM manufacturer-specific code (Chevrolet, GMC, Cadillac diesels) indicating the engine control module detected an implausible temperature reading from the exhaust Particulate Matter (PM/soot) sensor located downstream of the diesel particulate filter (DPF). The PM sensor uses an internal heater and temperature element to monitor soot accumulating between its electrodes; when the reported temperature does not match expected exhaust conditions, the ECM cannot trust the sensor's soot measurement and sets this code, often illuminating the check engine light and disabling proper DPF/emissions monitoring. Typical repair costs on Opel range from $200 to $600, depending on the specific model and root cause.
Common Causes of P118B
- •Faulty or aged exhaust particulate matter (PM) sensor
- •Open, shorted, or chafed wiring in the PM sensor harness
- •Poor electrical connection or corrosion at the PM sensor connector
- •Exhaust leak near the PM sensor altering measured temperature
- •Failed PM sensor internal heater or temperature element
- •ECM/sensor control unit software or calibration fault (less common)
P118B on Opel by Model
Opel Zafira(1 issue)
- NOx Sensor / SCR System Failure on Euro 6 Diesels (Zafira Tourer C)2015-2019
Euro 6 diesel Zafira Tourer C models with SCR/AdBlue (1.6 CDTi B16DTH and 2.0 CDTi B20DTH/D20DTH) commonly suffer NOx sensor failure. The upstream/downstream NOx sensors degrade and report implausible values, setting catalyst-efficiency and NOx-sensor codes (e.g. P20EE, P229F, P118B) and putting the car into reduced power / limp mode with an emissions warning and a restart countdown in some cases. German owners (motor-talk.de) report this as a known fault from around 80,000 km. NOx sensors are relatively expensive genuine parts and often fail again if cheap aftermarket units are used.
Looking for P118B on a different make?
View P118B across all makes →Frequently Asked Questions
What does P118B mean on Opel?▼
P118B stands for "Particulate Matter (PM) Sensor Temperature Not Plausible." P118B is a GM manufacturer-specific code (Chevrolet, GMC, Cadillac diesels) indicating the engine control module detected an implausible temperature reading from the exhaust Particulate Matter (PM/soot) sensor located downstream of the diesel particulate filter (DPF). The PM sensor uses an internal heater and temperature element to monitor soot accumulating between its electrodes; when the reported temperature does not match expected exhaust conditions, the ECM cannot trust the sensor's soot measurement and sets this code, often illuminating the check engine light and disabling proper DPF/emissions monitoring. On Opel specifically, this code is documented across 1 model.
What causes P118B on Opel vehicles?▼
Common causes on Opel: Faulty or aged exhaust particulate matter (PM) sensor, Open, shorted, or chafed wiring in the PM sensor harness, Poor electrical connection or corrosion at the PM sensor connector, Exhaust leak near the PM sensor altering measured temperature, Failed PM sensor internal heater or temperature element. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P118B on a Opel?▼
Repair costs on Opel range from $200 to $600, depending on the specific model and root cause.
Which Opel models have P118B documented?▼
Au7o has documented P118B on 1 Opel model: Zafira.