Your Vehicle: 2001 Ford Escort ZX2 L4-2.0L DOHC VIN 3
 
Vehicle » Powertrain Management » Computers and Control Systems » Testing and Inspection » Diagnostic Trouble Code Tests and Associated Procedures » SECTION 5: Pinpoint Tests » DG: Knock Sensor (KS) - Pinpoint Test  
 
 
  DG: Knock Sensor (KS) - Pinpoint Test  
 

DG: Knock Sensor (KS)

DG: Introduction See: DG: Knock Sensor (KS) - Introduction

DG1 DTC P0330, P0331 (KS2), DTC P0325, P0326 (KS1): CHECK VOLTAGE BETWEEN SENSOR AND SIG RTN

  • Verify that KS is connected and installed properly. Then complete comprehensive repair verification drive cycle. Refer to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.
  • Key on, engine off.
  • Access KS PID.
  • Read dc voltage.

Is the KS PID less than 0.5 volts?
Yes

  • KEY OFF. GO to DG2

.

No

  • GO to DG5

.

DG2 CHECK KS SENSOR RESISTANCE

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

  • Disconnect KS, measure resistance through the KS harness connector pins
  • For 4.2L: Measure resistance between (KS+) and (KS-) at the knock sensor.

Is resistance between 4.39 and 5.35 megaohms?
Yes

  • For Town Car, 5.4L E/F-Series (HD), and 6.8L

E/F-Series:

  • GO to DG6

.

  • All others:
  • GO to DG7

.

No

  • For resistance greater than 5.35 megaohms:
  • GO to DG3

.

  • For resistance less than 4.39 megohm:
  • GO to DG4

.

DG3 CHECK FOR OPEN OF KS CIRCUIT BETWEEN KS SIGRTN AND SHIELD IN HARNESS

  • Disconnect PCM.
  • Measure resistance of the KS+ circuit between the PCM harness connector pin and the KS harness connector.
  • For 4.2L:
  • Measure resistance of KS- circuit between the PCM harness connector pin and the KS connector.
  • Where applicable, measure resistance of shield between the PCM harness connector and the shield pin at the KS connector.

Is each resistance less than 5.0 ohms?
Yes

  • REPLACE KS.

No

  • REPAIR open circuit. COMPLETE Comprehensive Component Repair

Verification Drive Cycle. (REFER to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles)

DG4 CHECK KS CIRCUIT FOR SHORT TO GROUND IN HARNESS

  • Disconnect PCM.
  • Measure resistance between the KS- circuit at the PCM harness connector and chassis GND.
  • Measure resistance between the KS+ circuit at the PCM harness connector and chassis GND.
  • For 4.2L Only:
  • Measure resistance between the KS- and KS+ at the PCM harness connector.

Is each resistance greater than 10,000 ohms?
Yes

  • GO to DG7

.

No

  • SERVICE short circuit. COMPLETE Comprehensive Component Repair

Verification Drive Cycle. (REFER to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)

DG5 CHECK KS CIRCUITS FOR SHORT TO POWER IN HARNESS

  • Disconnect PCM.
  • Key on.
  • Measure voltage between the KS+ circuit at the PCM harness connector and battery negative post.
  • For 4.2L Only:
  • Measure voltage between the KS- circuit at the PCM harness connector and battery negative post.

Is each voltage less than 0.5 volt?
Yes

COMPLETE Comprehensive Component Repair Verification Drive Cycle. (REFER to
Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)

No

  • SERVICE short circuit. COMPLETE Comprehensive Component Repair

Verification Drive Cycle. (Refer to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)

DG6 CHECK SHIELD CIRCUIT RESISTANCE

  • Disconnect PCM.
  • Measure resistance of the KS shield between the PCM harness connector pin and the KS harness connector.

Is resistance less than 5.0 ohms?
Yes

  • GO to DG7
  1. COMPLETE Comprehensive Component Repair Verification Drive Cycle. (REFER to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)

No

  • REPAIR open circuit. COMPLETE Comprehensive Component Repair

Verification Drive Cycle. (REFER to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)

DG7 CHECK PCM FOR SHORT TO GROUND

  • Measure resistance between KS+ and SIG RTN circuits at the KS harness connector.
  • For 4.2L Only:
  • Measure resistance between KS+ and KS- circuits at the PCM harness connector.

Is resistance greater than 10,000 ohms?
Yes

  • REPLACE KS. If concern is still present, REPLACE PCM (refer

to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Programming and Relearning\Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM).
COMPLETE Comprehensive Component Repair Verification Drive Cycle. (REFER to
Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)

No

COMPLETE Comprehensive Component Repair Verification Drive Cycle. (REFER to
Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)

DG15 DTC P0325, P0326 (KS1), DTC P0330, P0331 (KS2): CHECK KS SENSOR VOLTAGE

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

  • Access KS PID.
  • Key on, engine off.

Is the KS PID between 2.2 and 2.6 volts?
Yes

  • KEY OFF. GO to DG16

.

No

  • GO to DG18

.

DG16 CHECK KS CIRCUIT FOR INTERMITTENT FAULT

  • Key on.
  • While viewing the voltmeter, grasp the vehicle harness as close to the knock sensor(s) as possible. Shake and bend a small section of the harness from the KS sensor to the PCM.
  • Tap the PCM and KS connectors if possible.

Is KS reading changing?
Yes

  • ISOLATE fault and SERVICE as required. COMPLETE Comprehensive

Component Repair Verification Drive Cycle. (REFER to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles
.)

No

  • GO to DG17

.

DG17 CHECK FOR KS VOLTAGE INCREASE

  • Start and run engine.
  • Monitor voltage at the knock sensor at idle and at 3000 rpm.

Does the AC voltage reading increase?
Yes

COMPLETE Comprehensive Component Repair Verification Drive Cycle. (REFER to
Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)

No

  • GO to DG18

.

DG18 CHECK KS CIRCUIT FOR OPEN IN HARNESS

  • PCM disconnected.
  • Disconnect suspect KS.
  • Measure resistance of the KS+ signal circuit between the PCM harness connector pin and the KS harness connector.
  • Measure resistance of the SIG RTN circuit between the PCM harness connector and the KS harness connector.

Is each resistance less than 5.0 ohms?
Yes

  • GO to DG19

.

No

  • REPAIR open circuit. COMPLETE Comprehensive Component Repair

Verification Drive Cycle. (REFER to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)

DG19 CHECK KS CIRCUIT FOR SHORT TO GROUND

  • Measure resistance of the KS+ circuit between the PCM harness connector pin and chassis GND.

Is resistance greater than 10,000 ohms?
Yes

  • REPLACE suspect KS. COMPLETE Comprehensive Component Repair

Verification Drive Cycle. (REFER to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)

No

  • REPAIR short circuit. COMPLETE Comprehensive Component Repair

Verification Drive Cycle. (REFER to Section 2, Drive Cycles See: SECTION 2: Diagnostic Methods\Drive Cycles.)