Circuit Test VAF - Volume Airflow Sensor
| Circuit | Breakout Box Pin No. | PCM Pin | Wire Color | |
|---|---|---|---|---|
| A/T | ||||
| SIG RTN | 46 | 3D | Black/White | |
| VAF | 44 | 2B | Red | |
| VREF | 26 | 2I | Light Green/Red | |
| M/T | ||||
| SIG RTN | 46 & 49 | 2D | Black/White | |
| VAF | 25 | 2O | Red | |
| VREF | 26 | 2K | Light Green/Red | |
1) Check System Integrity Visually check all wiring, connectors and components for evidence of damage, shorting or looseness. If fault is found, repair as necessary. If no fault is found, go to next step.
2) Check VAF Voltage Turn ignition off. Install breakout box. Connect PCM to breakout box. Access VAF measuring vane (air door). Turn ignition on. Measure voltage between VAF and SIG RTN test pins at breakout box while moving air door. If voltage is not as specified, go to next step. See VOLTAGE SPECIFICATIONS (VAF SENSOR) table. If voltage is as specified and no other problem or code is found, replace PCM.
3) Check VAF Signal From VAF Meter Turn ignition off. Access VAF measuring vane. Disconnect VAF meter connector. Connect a jumper wire between the VAF harness connector and VAF meter on VREF and SIG RTN wires. Turn ignition on. Measure voltage between VAF terminal at VAF meter and SIG RTN terminal at VAF meter connector while moving air door. Compare voltage to specifications shown in VOLTAGE SPECIFICATIONS (VAF SENSOR) table. If voltage is as specified, repair VAF wire to PCM. If voltage is not as specified, go to next step.
4) Check VREF At VAF Meter Turn ignition off. Disconnect VAF meter connector. Turn ignition on. Measure voltage between VREF and SIG RTN terminals at VAF meter connector. If voltage is 4.5-5.5 volts, replace VAF meter. If voltage is not 4.5-5.5 volts, go to CIRCUIT TEST VREF.
| Door Position | (1) Volts | ||
|---|---|---|---|
| 1/8 Open | 3.24 | ||
| 1/4 Open | 5.60 | ||
| 3/8 Open | 5.62 | ||
| 1/2 Open | 5.83 | ||
| 5/8 Open | 6.02 | ||
| 3/4 Open | 6.75 | ||
| 7/8 Open | 7.46 | ||
| Full Open | 7.87 | ||
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