P121A – Restricted Cylinder Balance Test Injector

P121A Possible Causes

  • Faulty fuel injector
  • Fuel injector harness is open or shorted
  • Poor electrical connection in fuel injector circuit

How is Code P121A 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 service engine soon warning light)

P121A Meaning

The Powertrain Control Module (PCM) monitors the fuel injector. The PCM sets the OBDII code when the fuel injector does not meet factory specifications.

P121A FORD – Restricted Cylinder Balance Test Injector

P121A FORD Possible Causes

  • Faulty fuel injector
  • Fuel injector harness is open or shorted
  • Poor electrical connection in fuel injector circuit

How to Fix P121A FORD 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)

P121A FORD Meaning

The Powertrain Control Module (PCM) monitors the fuel injector. The PCM sets the OBDII code when the fuel injector does not meet factory specifications.

P121B – Cylinder Balance Test Injector Blocked

P121B Possible Causes

  • Faulty fuel injector
  • Fuel injector harness is open or shorted
  • Poor electrical connection in fuel injector circuit

How to Fix Code P121B?

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)

P121B Meaning

The Powertrain Control Module (PCM) monitors the fuel injector. The PCM sets the OBDII code when the fuel injector does not meet factory specifications.

P121B FORD – Cylinder Balance Test Injector Stuck

P121B FORD Possible Causes

  • Faulty fuel injector
  • Fuel injector harness is open or shorted
  • Poor electrical connection in fuel injector circuit

How to Fix P121B FORD 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 service engine soon warning light)

P121B FORD Meaning

The Powertrain Control Module (PCM) monitors the fuel injector. The PCM sets the OBDII code when the fuel injector does not meet factory specifications.

P121C – Cylinder Balance Test Injector Leak

P121C Possible Causes

  • Faulty fuel injector
  • Fuel injector harness is open or shorted
  • Poor electrical connection in fuel injector circuit

How to Fix Code P121C?

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)

P121C Meaning

The Powertrain Control Module (PCM) monitors the fuel injector. The PCM sets the OBDII code when the fuel injector does not meet factory specifications.

P121C BMW – Nitrogen Oxide Sensor Heater Activation Short Circuit

P121C BMW Possible Causes

  • Faulty nitrogen oxide (NOx) sensor
  • Nitrogen oxide (NOx) sensor wiring harness is open or short-circuited
  • Poor electrical connection in the nitrogen oxide (NOx) sensor circuit
 

How to Fix BMW P121C 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

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

P121C BMW Meaning

The engine control module (ECM) monitors the nitrogen oxide (NOx) sensor. The ECM sets the OBDII code when the nitrogen oxide sensor does not meet factory specifications.

P121C FORD – Cylinder Balance Test Injector Leak

P121C FORD Possible Causes

  • Faulty fuel injector
  • Fuel injector harness is open or shorted
  • Poor electrical connection in fuel injector circuit

How to Fix Code P121C FORD?

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)

P121C FORD Meaning

The Powertrain Control Module (PCM) monitors the fuel injector. The PCM sets the OBDII code when the fuel injector does not meet factory specifications.

P121C MINI – Nitrogen Oxide Sensor Heater Activation Short Circuit

P121C MINI 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 P121C MINI 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 warning light soon)

P121C MINI Meaning

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

P121E – Disconnection of the Linear Oxygen Sensor Line from the Nitrogen Oxide Sensor

P121E Possible Causes

  • Faulty nitrogen oxide (NOx) sensor Linear oxygen sensor
  • Nitrogen oxide (NOx) sensor Linear oxygen sensor harness open or short circuit
  • Nitrogen oxide (NOx) sensor Linear oxygen sensor circuit poor electrical connection

How to Fix Code P121E?

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)

P121E Meaning

The engine control module (ECM) monitors the nitrogen oxide (NOx) sensor linear oxygen sensor. The ECM sets the OBDII code when the nitrogen oxide sensor linear oxygen sensor does not meet factory specifications.

P121E BMW – Disconnection of the Oxygen Sensor Line from the Nitrogen Oxide Sensor

P121E BMW Possible Causes

  • Faulty nitrogen oxide (NOx) sensor Linear oxygen sensor
  • Nitrogen oxide (NOx) sensor Linear oxygen sensor harness open or short circuit
  • Nitrogen oxide (NOx) sensor Linear oxygen sensor circuit poor electrical connection

How to Fix BMW P121E 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

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

P121E BMW Meaning

The engine control module (ECM) monitors the nitrogen oxide (NOx) sensor linear oxygen sensor. The ECM sets the OBDII code when the nitrogen oxide sensor linear oxygen sensor does not meet factory specifications.