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How To Use Pinpoint Tests

NOTE: A 104-pin Breakout Box (014-00950) connected to vehicle harness at PCM, is necessary to perform most pinpoint tests. References to Test Pin No. found in PINPOINT TEST steps refer to test terminals on 104-pin breakout box unless specified otherwise. Some transmission related circuit tests require the use of a 60-pin Breakout Box (007-00033) connected to vehicle harness at TCM. See TRANSMISSION CONTROL MODULE (TCM) under ON-VEHICLE SERVICE in FORD 4F20E OVERHAUL article for information regarding disconnecting TCM. Circuit information at beginning of each test identifies circuit and wire colors.
  1. DO NOT perform any PINPOINT TEST unless specifically instructed by a QUICK TEST  procedure. Follow each test step in order until fault is found. DO NOT replace any part unless directed to do so. When more than one code is retrieved, start with first code displayed.
  2. PINPOINT TESTS ensure electrical circuits are okay before sensors or other components are replaced. Always test circuits for continuity between sensor and PCM or TCM. Test all circuits for short to power, opens or short to ground. Voltage Reference (VREF) and Voltage Power (VPWR) circuits should be tested with ignition on or as specified in PINPOINT TESTS.
  3. DO NOT measure voltage or resistance at PCM or TCM, as harness and connector are easily damaged. DO NOT connect any type of test light unless specified in testing procedure. All measurements are made by probing rear of connector (wiring harness side), unless otherwise instructed. Isolate both ends of a circuit and turn ignition off when checking for shorts or continuity, unless instructed otherwise.
  4. Disconnect solenoids and switches from harness before measuring continuity and resistance or applying voltage. After each repair, check all component connections and repeat QUICK TEST  .
  5. An open circuit is defined as a resistance reading of greater than 10 k/ohms. This specification tolerance may be too high for some items in EEC system. If resistance approaches 5 ohms, always clean suspected connector and coat it with protective dielectric silicone grease. A short is defined as a resistance reading of less than 5 ohms to ground, unless stated otherwise in PINPOINT TEST.
NOTE: In following tests, circuit diagrams and illustrations are courtesy of Ford Motor Co.
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