664 Auto Electricity and Electronics Copyright by Goodheart-Willcox Co., Inc. Th e drive cycle is diff erent for each vehicle, so check the service manual for specifi c instructions. To begin the drive cycle, check that the coolant temperature is low enough to allow the ECM to start in the open loop mode. On most engines, coolant temperature should be below 120°F (49°C). Be sure to allow for variations in coolant temperature sen- sor calibration. In warm climates, the cool down period can take as long as six hours. If possible, allow the vehicle to sit overnight before starting the drive cycle. Attach the scan tool and set the tool to record the EMC status as the engine operates. Some scan tools have a dedicated drive cycle option. A typical drive cycle will cover engine warm-up, idling, accelerating, decelerating, and cruising, in a specifi c order, Figure 34-12. Th is order must Figure 34-11. Scan tool datastream values can be helpful when you have performance problems but no trouble codes. Datastream values are electrical values detected by the ECM. If values from a pinpoint test do not match datastream values, suspect wiring ECM problems. DATASTREAM VALUES For Cold Key On, Cold Idle and Hot Idle: Vehicle in PARK, A/C turned OFF, no power steering load, all ACC’s OFF, Brake Pedal Released. For 55 MPH Cruise: Vehicle in Drive 4, A/C turned ON and no power steering load, compare data after driving for approximately 1 mile. Scan Tool Parameter Display Units Data List Cold Key ON Cold Idle Hot Idle 55 MPH Cruise Engine Speed RPM ENG 1 0 Within 80 RPM of Desired Idle Within 80 RPM of Desired Idle 1730 Desired Idle RPM ENG 1 0 700 to 1200 550 to 675 720 MAF gms-sec ENG 1 0.0 9.8 to 11.0 5.0 to 6.0 20 to 28 TP Sensor V/° ENG 1 0.63/1.7 .60 mV/0.8° .60 mV/0.8° 1.06/11.0 ECT °C ENG 1 80° C –20°C to 50° C 90° C to 110° C 90° C to 110° C IAT °C ENG 1 80° C –20°C to 50° C 0° C to 90° C 0° C to 90° C MAP kP a/V ENG 1 97/4.63 30 to 50 kPa 1.5 V @ 38 kPa 30 to 50 kPa 1.5 V @ 38 kPa 64/2.88 BARO kP a/V ENG 1 97/4.63 85 to 103 kPa 85 to 103 kPa 98/4.69 TP Angle %/° ENG 1 0%/0.0° 0%/0.0° 0%/0.0° 11%/8.6° Engine Load % ENG 1 0% 1 to 5% 1 to 5% 13% Engine Speed RPM ENG 1 0 Within 80 RPM of Desired Idle Within 80 RPM of Desired Idle 1730 IAC Position counts ENG 1 160 Varies 30 to 80 100 Inj. PWM Bank 1 ms 0.0 3.75 to 4.50 3.20 to 3.75 5.1 ms Inj. PWM Bank 2 ms 0.0 3.75 to 4.50 3.20 to 3.75 5.2 ms HO 2 S Bn 1 Sen. 1 mV 67 Varies Varies Varies HO 2 S Bn 2 Sen. 1 mV 111 Varies Varies Varies Rich to Lean Status Bn 1 Sen. 1 Lean/Rich Lean Varies Varies Varies Rich to Lean Status Bn 2 Sen. 1 Lean/Rich Lean Varies Varies Varies HO 2 S Bn 1 Sen. 2 mV 45 Varies Varies Varies HO 2 S Bn 1 Sen. 3 mV 156 Varies 600 mV or more 600 mV or more Rich to Lean Status Bn 1 Sen. 2 Lean/Rich Lean Varies Varies Varies Rich to Lean Status Bn 1 Sen. 3 Lean/Rich Lean Varies Varies Varies Fuel Trim Cell Number 0 16 16 5 Fuel Trim Learn Disabled/ Enabled Disabled Disabled Enabled Enabled Shrt Term FT Bn 1 % 0%/128 –2.0 to 2.0 –3.0 to 3.0 –6.0 to 6.0