TEST EQUIPMENT
All voltage tests should be performed with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless specifically stated differently in testing procedure.
Use Backprobe Set (07SAZ-001000A ) (2 required) to backprobe Powertrain Control Module (PCM) when directed by testing. (Scheme 4) For PCM connector terminal identification, see CONNECTOR IDENTIFICATION. DO NOT puncture wire insulation. Place scan tool probe into contact with terminal, from terminal side of wiring harness connectors in engine compartment. For female connectors, just touch terminal lightly with scan tool probe. DO NOT insert probe into terminal.
Scheme 4
Scheme 5
Scheme 6
Intermittent Symptom
If symptom is intermittent, check for loose fuse No. 25 METER (7.5-amp). Fuse is located in underdash fuse/relay box. Also check for poor connection at PCM connector terminal A18 or an intermittent open in wire between PCM connector terminal A18 and gauge assembly. See the WIRING DIAGRAMS article.