P11C4 Possible Causes

• Faulty intake air humidity sensor
• Intake air humidity sensor harness is open or shorted
• Poor electrical connection in the intake air humidity sensor circuit

How is code P11C4 repaired?

Start by checking the “possible causes” listed above. Visually inspect the corresponding cable harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Technical Notes

Possible Symptoms

• Engine light on (or engine service warning light soon)

P11C4 Meaning

The Powertrain Control Module (PCM) monitors the intake air humidity sensor signal. The PCM sets the OBDII code when the intake air humidity sensor does not meet factory specifications.

P11C8 Possible Causes

• Faulty pedal position sensor
• Pedal position sensor harness is open or shorted
• Poor electrical connection in pedal position sensor circuit

How to Fix Code P11C8?

Start by checking the “Possible Causes” listed above. Visually inspect the corresponding cable harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

• Engine light on (or engine warning light soon to come on)

P11C8 Meaning

The Engine Control Module (ECM) monitors the pedal position sensor. The ECM sets the OBDII code when the pedal position sensor does not meet factory specifications.

P11C9 Possible Causes

• Faulty Intake Air Temperature (IAT) sensor
• Intake Air Temperature (IAT) sensor harness is open or shorted
• Poor electrical connection in the Intake Air Temperature (IAT) sensor circuit

How is code P11C9 repaired?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

• Check Engine Light on (or service engine soon warning light)

P11C9 Meaning

The Intake Air Temperature (IAT) sensor is a temperature-sensitive variable resistor that measures the air temperature in the intake system. The sensor’s resistance will change depending on the air temperature. The higher the temperature, the lower the resistance. The Engine Control Module (ECM) provides a reference voltage and monitors the voltage drop between a fixed-value internal resistor and the sensor’s resistance. This is called a voltage divider circuit.
IAT sensor values are used by the ECM processor to help calculate idle speed, fuel mixture, and ignition timing.
Inaccurate IAT sensor voltages can affect pulse width, idle quality, and tailpipe emissions. Intermittent signals can cause hesitation, stumbling, and surging. If an IAT sensor failure accompanies an Engine Coolant Temperature (ECT) sensor failure, cooling fan operation may also be affected.
Some manufacturers integrate the Intake Air Temperature (IAT) sensor as part of the Mass Air Flow (MAF) sensor (air flow meter).

P11CB Possible Causes

• Faulty barometric pressure sensor
• Barometric pressure sensor harness is open or shorted
• Poor electrical connection in the barometric pressure sensor circuit

How is Code P11CB Repaired?

Start by checking the “possible causes” listed above. Visually inspect the corresponding cable harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

• Check Engine Light on (or Service Engine Soon warning light)

P11CB Meaning

The Engine Control Module (ECM) monitors the barometric pressure sensor. The ECM sets the OBDII code when the barometric pressure sensor does not meet factory specifications.

P11CB GMC Possible Causes

• Faulty NOx sensor 1
• NOx sensor 1 harness is open or shorted
• Poor electrical connection in NOx sensor 1 circuit
• Intake system leaks
• Exhaust system leaks

How is GMC P11CB Code Repaired?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

• Engine light on (or engine service soon warning light)

P11CB GMC Meaning

The Powertrain Control Module (PCM) monitors NOx sensor 1. The PCM sets the OBDII code when NOx sensor 1 does not meet factory specifications.

P11CB CHEVROLET Possible Causes

• Faulty NOx sensor 1
• NOx sensor 1 harness is open or shorted
• Poor electrical connection in NOx sensor 1 circuit
• Intake system leaks
• Exhaust system leaks

How to Fix Code P11CB CHEVROLET?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

• Engine light on (or service engine soon warning light)

P11CB CHEVROLET Meaning

The Powertrain Control Module (PCM) monitors NOx sensor 1. The PCM sets the OBDII code when NOx sensor 1 does not meet factory specifications.

Possible Causes of P11CC

• Faulty Nox sensor 1
• Nox sensor 1 harness is open or shorted
• Poor electrical connection in Nox sensor 1 circuit
• Intake system leaks
• Exhaust system leaks

How is P11CC Code Repaired?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

• Engine light on (or engine service soon warning light)

Meaning of P11CC

The Powertrain Control Module (PCM) monitors the Nox sensor 1. The PCM sets the OBDII code when the Nox sensor 1 does not meet factory specifications.

P11CC CHEVROLET Possible Causes

• Faulty NOx sensor 1
• NOx sensor 1 harness is open or shorted
• Poor electrical connection in NOx sensor 1 circuit
• Intake system leaks
• Exhaust system leaks

How to Fix P11CC CHEVROLET Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

• Engine light on (or engine service soon warning light)

P11CC CHEVROLET Meaning

The Powertrain Control Module (PCM) monitors NOx sensor 1. The PCM sets the OBDII code when NOx sensor 1 does not meet factory specifications.

P11CE Possible Causes

• Faulty accelerator pedal
• Accelerator pedal harness is open or short-circuited
• Poor electrical connection of the accelerator pedal circuit
• Faulty accelerator pedal module

How is code P11CE repaired?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

• Engine light on (or engine service warning light soon)

P11CE Meaning

The accelerator pedal position is separately monitored by 2 individual sensors. Two sensors are used to ensure redundancy, implement monitoring functions, and facilitate malfunction detection. The sensors record the accelerator pedal travel as angular deflection, with data transmitted directly to the engine management control unit as analog linear voltage curves for the pedal angle. The total pedal travel is mechanically expressed as 16° ± 0.5°.
Each change in accelerator pedal position is transmitted to the engine management computer with a maximum delay of 50 milliseconds. The sensor signals are transmitted in analog form. The engine management control unit monitors both sensor input signals and compares them for plausibility (factors such as mutual synchrony, linearity, etc.).
The digital motor electronics (DME) diagnose the voltage at sensor pedal 1 of the accelerator pedal module. The diagnostic trouble code (DTC) is detected if the voltage at pedal sensor 1 is below a lower threshold value. Lower threshold value: 0.51 V.

P11D7 Possible Causes

• Faulty nitrogen oxide (NOx) sensor
• Nitrogen oxide (NOx) sensor harness is open or shorted
• Poor electrical connection in the nitrogen oxide (NOx) sensor circuit

How to Fix Code P11D7?

Start by checking the “possible causes” listed above. Visually inspect the corresponding cable harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

• Check Engine Light On (or Service Engine Soon Warning Light)

P11D7 Meaning

The reduction system uses two nitrogen oxide (NOx) sensors to monitor the amount of NOx in the engine exhaust gases. The first sensor is located at the turbocharger outlet and monitors the engine’s NOx level. The second NOx sensor is located between the selective catalytic reduction (SCR) and the diesel particulate filter (DPF) and monitors NOx levels downstream of the SCR. The second NOx sensor also provides the Engine Control Module (ECM) with information about the exhaust oxygen level during DPF regeneration.
Each NOx sensor contains a sensing cell, a pumping cell, and a heater. An exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The NOx sensor maintains a constant reference voltage across the sensing cell. An electronic circuit inside the sensor controls the pump current through the pumping cell to maintain a constant voltage in the sensing cell. The amount of current required to maintain the reference voltage in the sensing cell is proportional to the NOx concentration in the exhaust.
The ECM varies the amount of diesel exhaust fluid (DEF) or reductant added by varying the duty cycle of the reductant injector in response to changes in engine exhaust NOx levels.
Intelligent NOx sensors consist of two components, the NOx module and the NOx sensor element, which are serviced as a unit. A circuit or performance condition with a NOx sensor is detected by the NOx sensor module. The intelligent NOx sensor module communicates the condition to the ECM via the serial data line. The ECM sets a DTC when a serial data message is received from the NOx sensor module.