Diagnostic Aids
NOTE:
After each service or repair procedure has been completed, reconnect all components. Clear DTCs and perform COMPREHENSIVE COMPONENT MONITOR REPAIR VERIFICATION DRIVE CYCLE. See DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. After drive cycle is complete, repeat QUICK TEST procedures to ensure all EEC-V systems are working properly and DTCs are no longer present.
Perform this test only when directed by QUICK TEST. This test is intended to diagnose the following.
- Knock Sensor (KS)
- Wiring Harness Circuits (KS & SIG RTN)
- Powertrain Control Module (PCM)
To prevent replacement of good components, be aware the following non-EEC related areas may be at fault:
- Poor Fuel Quality
- Ignition System
- Ignition Or Valve Timing
- Engine Mechanical Condition
NOTE:
For knock sensor circuits and connector identification, refer to illustrations. See Fig 1-Fig 7
.
NOTE:
Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION table of fault code setting condition.
FAULT CODE SETTING CONDITION
| Fault Code | KOEO | KOER | Continuous Memory |
|---|---|---|---|
| P0325 (E Series) | DG15 | DG15 | |
| P0325 | DG1 | DG1 | |
| P0326 (E Series) | DG15 | DG15 | |
| P0326 | DG1 | DG1 | |
| P0330 (E Series) | DG15 | DG15 | |
| P0330 | DG1 | DG1 | |
| P0331 (E Series) | DG15 | DG15 | |
| P0331 | DG1 | DG1 |
- 1) KOER & Continuous Memory DTCs P0325, P0326 (KS1), Or P0330 & P0331 (KS2): Check Knock Sensor Voltage
DTCs P0325, P0326, P0330 and P0331 indicate spark knock voltage fell below minimum calibrated limit or exceeded maximum calibrated limit. DTC P0325 and P0326 are for knock sensor No. 1 (cylinder bank that includes cylinder No. 1). DTCs P0330 and P0331 are for knock sensor No. 2. Possible causes for these faults are.- Open In KS Circuit
- KS Circuit Shorted To PWR Or GND
- Faulty Knock Sensor
- Faulty Powertrain Control Module (PCM)
Turn ignition switch to OFF position. Ensure knock sensor is connected. Perform DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. Ensure COMPREHENSIVE COMPONENT MONITOR (CCM) MONITOR (TRANSMISSION) PROCEDURE is performed. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, select KS PID from PID/DATA MONITOR & RECORD menu. If PID voltage is less than .5 volt, go to next step. If PID voltage is .5 volt or more, go to step 6).
- 2) Check Knock Sensor Circuit Resistance
Turn ignition switch to OFF position. Disconnect PCM connector(s). Measure resistance between specified PCM harness connector KS (+) and KS (-) terminals. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If resistance is 4.39-5.35 megohms, go to step 6) (Econoline/Pickup 5.4L and 6.8L, and Town Car), or go to step 7) (all others). If resistance is more than 5.35 megohms, go to next step. If resistance is less than 4.39 megohms, go to step 5).KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATIONApplication PCM KS (-) Terminal No. PCM KS (+) Terminal No. Continental & Mustang 4.6L (4V) Bank 1 32 57 Bank 2 23 102 Cougar, Escort & Focus 2.0L (2V) 87 57 Econoline 4.6L, Econoline & Pickup 5.4L (Heavy-Duty), & Town Car 91 57 LS (All Engines) Bank 1 C42 C51 Bank 2 C43 C52 All Others 32 57 - 3) Check Knock Sensor Resistance
Turn ignition switch to OFF position. Disconnect KS connector. Measure resistance between both KS connector terminals. If resistance is 4.39-5.35 megohms, go to next step. If resistance is not 4.39-5.35 megohms, replace KS. - 4) Check For Open Circuit
Ensure PCM connector(s) is disconnected. Measure resistance of KS (+) and KS (-) circuits between PCM harness connector and knock sensor harness connector. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If both resistance measurements are less than 5 ohms, go to step 7). If either resistance measurement is 5 ohms or more, repair open in affected circuit. - 5) Check For Short Between KS (+) & KS (-) Circuits
Disconnect KS connector. Measure resistance between specified PCM harness connector KS (+) and KS (-) terminals. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If resistance is more than 10 k/ohms, go to step 7). If resistance is 10 k/ohms or less, repair short between circuits. - 6) Check KS Circuits For Short To Power
Turn ignition switch to OFF position. Disconnect PCM connector(s). Turn ignition switch to ON position. Measure voltage between specified PCM harness connector KS (+) and KS (-) terminals and battery negative terminal. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If voltage is less than .5 volt, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . If voltage is .5 volt or more, repair short to VPWR in affected circuit. - 7) Check KS Circuits For Short To Ground
Ensure ignition switch is turned to OFF position. Connect PCM harness connector(s). Measure resistance between KS harness connector KS (+) and KS (-) terminals and battery negative terminal. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If resistance is 10 k/ohms or less, go to next step. If resistance is more than 10 k/ohms, replace knock sensor. Reconnect all components and repeat QUICK TEST . If fault is still present, go to next step. - 8) Check PCM For Short To Ground
Ensure ignition switch is turned to OFF position. Disconnect PCM harness connector(s). Measure resistance between KS harness connector KS (+) and KS (-) terminals. If resistance is 10 k/ohms or less, repair short to ground in affected circuit. If resistance is more than 10 k/ohms, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . Reconnect all components and repeat QUICK TEST .NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 8) to step 15). No test procedures have been omitted. Steps 15) through 19) apply to Sable, Taurus, and Econoline 4.6L only. - 15) DTCs P0325, P0326 (KS1) Or P0330, P0331 (KS2): Check Knock Sensor Voltage
DTCs P0326 (KS1) and P0331 (KS2) indicate spark knock has not been sensed. DTCs P0325 (KS1) and P0330 (KS2) indicate spark knock system failed. Possible causes for these faults are:- Open Or Short In Harness
- Faulty Knock Sensor (KS)
- Faulty Powertrain Control Module (PCM)
Turn ignition switch to ON position. Using scan tool, select KS PID from PID/DATA MONITOR & RECORD menu. If PID voltage is 2.2-2.6 volts, turn ignition switch to OFF position and go to next step. If PID voltage is not 2.2-2.6 volts, go to step 18).
- 16) Check For Intermittent Circuit Fault
While observing KS PID voltage, wiggle small sections of wiring harness starting at the knock sensor working toward PCM. If fault is indicated (voltage changes), isolate fault and repair as necessary. If no fault is indicated, go to next step. - 17) Check For Voltage Increase
Turn ignition switch to OFF position. Disconnect scan tool from Data Link Connector (DLC). Set voltmeter on AC scale. Start engine and allow to idle. Measure voltage between suspect sensor terminals. Note voltage measurement. Raise engine speed to 3000 RPM. If AC voltage does not increase, go to next step. If AC voltage increases, proceed as follows:- If no DTCs are present, no problem is indicated at this time. Diagnose by symptom. See TROUBLE SHOOTING - NO CODES - EEC-V (GASOLINE) article.
- If any DTCs are present, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE .
- 18) Check Circuit Resistance
Turn ignition switch to OFF position. Disconnect PCM connector(s). Disconnect suspect knock sensor. Measure resistance of KS circuit (KS, KS1 or KS2) between suspect sensor harness connector and appropriate PCM harness connector terminal. Measure resistance of SIG RTN circuit between suspect sensor harness connector and appropriate PCM harness connector terminal. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If both resistance measurements are less than 5 ohms, go to next step. If any resistance measurement is 5 ohms or more, repair open circuit. - 19) Check Circuit For Short To Ground
Measure resistance of KS+ circuit between appropriate PCM harness connector terminal and ground. If resistance is more than 10 k/ohms, replace knock sensor. If resistance is 10 k/ohms or less, repair short circuit.
Fig 1: Identifying Knock Sensor Circuits (Contour, Cougar, Econoline - 4.2L, Escort - 2.0L 4V, Excursion, Expedition, Explorer - 4.0L SOHC, Focus - 2.0L 4V, Mountaineer - 4.0L SOHC, Mystique, Navigator & Pickup - 4.2L, 4.6L & 5.4L Light-Duty)
Fig 4: Identifying Knock Sensor Circuits & Connector Terminals (Econoline - 5.4L Super-Duty & 6.8L, Pickup - 5.4L Super-Duty & 6.8L & Town Car