Your Vehicle: 2001 Ford Escort ZX2 L4-2.0L DOHC VIN 3
 
Vehicle » Powertrain Management » Computers and Control Systems » Testing and Inspection » Pinpoint Tests » JH: Tachometer Output Failure - Pinpoint Test  
 
 
  JH: Tachometer Output Failure - Pinpoint Test  
 

JH: Tachometer Output Failure

JH: Introduction See: JH: Tachometer Output Failure - Introduction

JH1 CHECK CTO CIRCUIT FOR SHORT TO POWER IN HARNESS

  • Disconnect PCM.
  • Key on, engine off.
  • Measure voltage of CTO circuit between PCM harness connector pin 48 and ground.

Is the voltage less than 0.5 volt?
Yes

  • KEY OFF. GO to JH2

.

No

  • REPAIR short circuit. VERIFY symptom no longer exists.

JH2 CHECK CTO CIRCUIT FOR SHORT TO GROUND IN HARNESS

  • Disconnect instrument cluster connector.
  • Measure resistance between PCM harness connector pin 48 and battery negative post.
  • Measure resistance between PCM harness connector pin 48 and chassis ground.

Are both resistances greater than 10,000 ohms?
Yes

  • GO to JH3

.

No

  • REPAIR short circuit. VERIFY a symptom no longer exists.

JH3 CHECK CTO CIRCUIT FOR OPEN IN HARNESS

  • Measure resistance between PCM harness connector pin 48 and instrument cluster harness pin.

Is the resistance less than 5.0 ohms?
Yes

  • GO to JH4

.

No

  • REPAIR open circuit. VERIFY symptom no longer exists.

JH4 CHECK CTO SIGNAL FROM PCM

  • Reconnect PCM.
  • Start engine.
  • Measure voltage between CTO pin at the instrument cluster and battery negative post.

Is voltage between 3.0 and 9.0 volts?
Yes

  • REFER to the Instrument Panel, Gauges and Warning Indicators.

No