Technical Definition:

Knock (Sensor 1) Circuit (Bank 1) or Single Sensor

Technical Description:

A knock sensor tells the engine computer when one or more of your engine’s cylinders are “knocking”, that is, exploding the air/fuel mixture in a way that delivers less power and can be damaging to the engine if prolonged.

Possible Causes:

• The knock sensor is faulty and needs to be replaced
• There is a wiring short/fault in the knock sensor circuit

Possible Symptoms:

Knock Sensor Circuit Malfunction

Possible Solutions:

• Check the resistance of the knock sensor (compare it to factory specs)
• Check for broken/frayed wires leading to the sensor
• Replace the knock sensor

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty knock sensor
– Knock sensor circuit poor electrical connection
– Knock sensor harness is open or shorted
– Faulty Engine Control Module (ECM)

Specific Makes:

– Possible Lack/Loss of Power

Technical Definition:

Knock Sensor 1) Circuit Range / Performance (Bank 1 or Single Sensor

Technical Description:

Knock sensors are used to detect engine pre-detonation (engine knock or ping). The knock sensor (KS) is usually a two wire sensor. A 5 volt reference is supplied to the sensor and there is a signal return from the knock sensor to the PCM (powertrain control module).

Possible Causes:

• Knock sensor connector is damaged
• Knock sensor circuit is open or shorted to ground
• Knock sensor circuit is shorted to voltage
• Knock sensor has failed
• Moisture in knock sensor connectors
• Incorrect fuel octane
• PCM has failed

Possible Symptoms:

• MIL (Malfunction Indicator Lamp) illumination
• Audible knocking from the engine compartment
• Pinging from engine under acceleration

Knock Sensor Circuit Range/Performance

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty knock sensor
– Knock sensor circuit poor electrical connection
– Knock sensor harness is open or shorted
– Faulty Engine Control Module (ECM)

Specific Makes:

– Possible Lack/Loss of Power

Technical Definition:

Knock Sensor 1) Circuit Low (Bank 1 or Single Sensor

Technical Description:

A knock sensor tells the engine computer when one or more of your engine’s cylinders are “knocking”, that is, exploding the air/fuel mixture in a way that delivers less power and can be damaging to the engine if prolonged.

Possible Causes:

• The knock sensor is faulty and needs to be replaced
• There is a wiring open/short/fault in the knock sensor circuit
• The PCM/ECM has failed

Possible Symptoms:

Knock Sensor Circuit Low Input

Possible Solutions:

• Verify the resistance of the knock sensor (compare it to factory specs)
• Inspect for broken/frayed wires leading to the sensor
• Check the wiring and connections leading to/from the knock sensor and PCM/ECM
• Verify proper voltage is reaching the knock sensor (e.g. 5 volts)
• Verify proper grounding of sensor and circuit
• Replace the knock sensor
• Replace the PCM/ECM

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty knock sensor
– Knock sensor circuit poor electrical connection
– Knock sensor harness is open or shorted
– Faulty Engine Control Module (ECM)

Specific Makes:

– Possible Lack/Loss of Power

Technical Definition:

Ignition / Distributor Engine Speed Input Circuit Intermittent

Technical Description:

Possible Causes:

Possible Symptoms:

Ignition/Distributor Engine Speed Input Circuit Intermittent

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Ignition/Distributor engine speed sensor harness is open or shorted
– Ignition/Distributor engine speed sensor circuit poor electrical connection
– Faulty Ignition/Distributor engine speed sensor
– Faulty Crankshaft Position sensor
– Low battery charge
– Faulty Engine Control Module (ECM)

Specific Makes:

– Lack/Loss of Power
– The engine may be harder to start
– The engine may stumble or stall

Technical Definition:

Knock Control System Error

Technical Description:

Possible Causes:

Possible Symptoms:

Knock Control System Error

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty knock sensor
– Knock sensor circuit poor electrical connection
– Knock sensor harness is open or shorted
– Faulty Engine Control Module (ECM)

Specific Makes:

– Possible Lack/Loss of Power

Technical Definition:

Ignition / Distributor Engine Speed Input Circuit No Signal

Technical Description:

Possible Causes:

Possible Symptoms:

Ignition/Distributor Engine Speed Input Circuit No Signal

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Ignition/Distributor engine speed sensor
– Ignition/Distributor engine speed sensor harness is open or shorted
– Ignition/Distributor engine speed sensor circuit poor electrical connection
– Faulty Crankshaft Position sensor
– Low battery charge
– Faulty Engine Control Module (ECM)

Specific Makes:

– Lack/Loss of Power
– The engine may be harder to start
– The engine may stumble or stall

Technical Definition:

Rough Road Hardware Not Present

Technical Description:

Possible Causes:

Possible Symptoms:

Rough Road Hardware Not Present

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

Specific Makes:

Technical Definition:

Rough Road (Sensor A) Signal Circuit

Technical Description:

Possible Causes:

Possible Symptoms:

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

Specific Makes:

Technical Definition:

Rough Road (Sensor B) Signal Circuit

Technical Description:

Possible Causes:

Possible Symptoms:

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

Specific Makes:

Technical Definition:

Ignition / Distributor Engine Speed Input Circuit

Technical Description:

Possible Causes:

Possible Symptoms:

Ignition/Distributor Engine Speed Input Circuit

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Ignition/Distributor engine speed sensor
– Faulty Crankshaft Position sensor
– Ignition/Distributor engine speed sensor harness is open or shorted
– Ignition/Distributor engine speed sensor circuit poor electrical connection
– Low battery charge
– Faulty Engine Control Module (ECM)

Specific Makes:

– Lack/Loss of Power
– The engine may be harder to start
– The engine may stumble or stall

Technical Definition:

Ignition / Distributor Engine Speed Input Circuit Range / Performance

Technical Description:

Possible Causes:

Possible Symptoms:

Ignition/Distributor Engine Speed Input Circuit Range/Performance

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Ignition/Distributor engine speed sensor
– Ignition/Distributor engine speed sensor harness is open or shorted
– Ignition/Distributor engine speed sensor circuit poor electrical connection
– Faulty Crankshaft Position sensor
– Low battery charge
– Faulty Engine Control Module (ECM)

Specific Makes:

– Lack/Loss of Power
– The engine may be harder to start
– The engine may stumble or stall

Technical Definition:

Crankshaft Position (CKP) System Variation Not Learned

Technical Description:

Possible Causes:

Possible Symptoms:

Crankshaft Position System Variation Not Learned

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Crankshaft Position (CKP)
– Crankshaft Position (CKP) sensor harness is open or shorted
– Crankshaft Position (CKP) sensor circuit poor electrical connection
– Damaged crankshaft pulse wheel teeth

Specific Makes:

– Engine fails to start
– Engine runs rough

Technical Definition:

Engine Misfire Detected on Startup (First 1000 Revolutions)

Technical Description:

Possible Causes:

• Damaged or defective Crankshaft Position Sensor (CKP)
• CKP sensor wiring or connector fault
• Poor fuel quality
• Ran out of fuel
• Ignition system malfunction
• Fuel system malfunction: injector or fuel pump
• Mechanical engine problem
• Damaged PCM

Possible Symptoms:

• MIL (Malfunction indicator lamp) illumination
• Rough engine start or idle

Engine Misfire Detected on Startup

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Crankshaft Position (CKP)
– Crankshaft Position (CKP) sensor harness is open or shorted
– Crankshaft Position (CKP) sensor circuit poor electrical connection
– Ignition System
– Fuel Injectors
– Running out of fuel
– Fuel Quality
– Faulty Engine Control Module (ECM)

Specific Makes:

– Engine fails to start
– Engine runs rough

Technical Definition:

Cylinder 11 Misfire Detected

Technical Description:

Possible Causes:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• Defective computer

Possible Symptoms:

• The engine may be harder to start
• The engine may stumble / stumble, and/or hesitate
• Other symptoms may also be present

Cylinder 11 Misfire Detected

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty spark plug 11
– Clogged or faulty fuel injector 11
– Faulty ignition coil 11
– Fuel injector 11 harness is open or shorted
– Fuel injector 11 circuit poor electrical connection
– Ignition coil 11 harness is open or shorted
– Ignition coil 11 circuit poor electrical connection
– Insufficient cylinder 11 compression
– Incorrect fuel pressure
– Intake air leak

Specific Makes:

– Lack/loss of power
– Hard start
– Engine hesitation

Technical Definition:

Cylinder 12 Misfire Detected

Technical Description:

Possible Causes:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• Defective computer

Possible Symptoms:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

Cylinder 12 Misfire Detected

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty spark plug 12
– Clogged or faulty fuel injector 12
– Faulty ignition coil 12
– Fuel injector 12 harness is open or shorted
– Fuel injector 12 circuit poor electrical connection
– Ignition coil 12 harness is open or shorted
– Ignition coil 12 circuit poor electrical connection
– Insufficient cylinder 12 compression
– Incorrect fuel pressure
– Intake air leak

Specific Makes:

– Lack/loss of power
– Hard start
– Engine hesitation

Technical Definition:

Misfire Detected With Low Fuel

Technical Description:

Possible Causes:

Possible Symptoms:

Misfire Detected With Low Fuel

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Not enough fuel in tank
– Faulty spark plugs plug wires
– Faulty injectors
– Vacuum leaks
– Faulty Fuel Sender Unit
– Fuel Sender Unit harness open or shorted
– Fuel Sender Unit poor electrical connection

Specific Makes:

Technical Definition:

Single Cylinder Misfire (Cylinder not Specified)

Technical Description:

Possible Causes:

Possible Symptoms:

Single Cylinder Misfire

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

Specific Makes:

Technical Definition:

Cylinder 7 Misfire Detected

Technical Description:

Possible Causes:

Possible Symptoms:

Cylinder 7 Misfire Detected

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty spark plug 7
– Clogged or faulty fuel injector 7
– Faulty ignition coil 7
– Fuel injector 7 harness is open or shorted
– Fuel injector 7 circuit poor electrical connection
– Ignition coil 7 harness is open or shorted
– Ignition coil 7 circuit poor electrical connection
– Insufficient cylinder 7 compression
– Incorrect fuel pressure
– Intake air leak

Specific Makes:

– Lack/loss of power
– Hard start
– Engine hesitation

Technical Definition:

Cylinder 8 Misfire Detected

Technical Description:

Possible Causes:

Possible Symptoms:

Cylinder 8 Misfire Detected

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty spark plug 8
– Clogged or faulty fuel injector 8
– Faulty ignition coil 8
– Fuel injector 8 harness is open or shorted
– Fuel injector 8 circuit poor electrical connection
– Ignition coil 8 harness is open or shorted
– Ignition coil 8 circuit poor electrical connection
– Insufficient cylinder 8 compression
– Incorrect fuel pressure
– Intake air leak

Specific Makes:

– Lack/loss of power
– Hard start
– Engine hesitation

Technical Definition:

Cylinder 9 Misfire Detected

Technical Description:

Possible Causes:

Possible Symptoms:

Cylinder 9 Misfire Detected

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty spark plug 9
– Clogged or faulty fuel injector 9
– Faulty ignition coil 9
– Fuel injector 9 harness is open or shorted
– Fuel injector 9 circuit poor electrical connection
– Ignition coil 9 harness is open or shorted
– Ignition coil 9 circuit poor electrical connection
– Insufficient cylinder 9 compression
– Incorrect fuel pressure
– Intake air leak

Specific Makes:

– Lack/loss of power
– Hard start
– Engine hesitation