Handling No Trouble Code Problems

HANDLING NO TROUBLE CODE PROBLEMS
Symptom checks cannot be used properly unless driveability problem characteristic actually happens while the vehicle is being tested.

Select the symptom that most accurately describes the vehicle's driveability problem and then perform the test routine that pertains to this symptom.Perform each routine test in sequence until problem is found. For definitions see Glossary Of Terms.

SYMPTOM DIAGNOSTIC TEST

Hard Start Checking secondary ignition system
Checking engine vacuum
Checking fuel pressure
Checking ECT sensor calibration
Checking TPS calibration
Checking MAP sensor calibration
Checking the minimum idle air flow
Checking IAC motor operation
Checking engine mechanical systems
Checking EVAP emission system
Checking EGR system
Checking IAT sensor

Start And Stall Checking secondary ignition system
Checking PCM power and ground circuits
Checking fuel pressure
Checking ECT sensor calibration
Checking TPS calibration
Checking MAP sensor calibration
Checking the minimum idle air flow
Checking IAC operation

Hesitation / Sag / Stumble Checking secondary ignition system
Checking PCM power and ground circuits
Checking engine vacuum
Checking fuel pressure
Checking ECT sensor calibration
Checking TPS calibration
Checking MAP sensor calibration
Checking the minimum idle air flow
Checking for oxygen sensor switching
Checking O2 sensor heater
Checking IAC motor operation
Checking engine mechanical systems
Checking EVAP emission system
Checking EGR system
Checking IAT sensor
Checking PNP switch

Surge Checking secondary ignition system
Checking PCM power and ground circuits
Checking fuel pressure
Checking ECT sensor calibration
Checking TPS calibration
Checking MAP sensor calibration
Checking minimum idle air flow
Checking for oxygen sensor switching
Checking IAC motor operation
Checking EVAP emission system

Lack Of Power / Sluggish Checking secondary ignition system
Checking PCM power and ground circuits
Checking fuel pressure
Checking ECT sensor calibration
Checking TPS calibration
Checking MAP sensor calibration
Checking minimum idle air flow
Checking for oxygen sensor switching
Checking IAC motor operation
Checking EGR system

Spark Knock / Detonation Checking secondary ignition system
Checking PCM power and ground circuits
Checking fuel pressure
Checking ECT sensor calibration
Checking TPS calibration
Checking MAP sensor calibration
Checking the minimum idle air flow
Checking for oxygen sensor switching
Checking IAC motor operation
Checking EVAP emission system

Cuts Out / Misses Checking secondary ignition system
Checking PCM power and ground circuits
Checking fuel pressure
Checking minimum idle air flow
Checking for oxygen sensor switching
Checking IAC motor operation
Checking EGR system

Backfire / Popback Checking secondary ignition system
Checking PCM power and ground circuits
Checking fuel pressure
Checking MAP sensor calibration
Checking minimum idle air flow
Checking for oxygen sensor switching
Checking EGR system

Runs Rough / Unstable / Checking secondary ignition system
Erratic Idle / Stalling Checking PCM power and ground circuits
Checking engine vacuum
Checking fuel pressure
Checking ECT sensor calibration
Checking TPS calibration
Checking MAP sensor calibration
Checking minimum idle air flow
Checking for oxygen sensor switching
Checking O2 sensor heater
Checking IAC motor operation
Checking engine mechanical systems
Checking EVAP emission system
Checking EGR system
Checking IAT sensor
Checking PNP switch

Poor Fuel Economy Checking secondary ignition system
Checking PCM power and ground circuits
Checking engine vacuum
Checking fuel pressure
Checking ECT sensor calibration
Checking TPS calibration
Checking MAP sensor calibration
Checking minimum idle air flow
Checking for oxygen sensor switching
Checking O2 sensor heater
Checking IAC motor operation
Checking engine mechanical systems
Checking EVAP emission system
Checking EGR system
Checking IAT sensor
Checking PNP switch