Diagnostic Aids

WARNING: This page is about a different car, the 2002 Isuzu Rodeo Sport and 2002 Isuzu Rodeo. However, it is still accessible from the selected car via links, so may be relevant.

Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If harness appears to be okay, use scan tool to observe HO2S readings while moving connectors and harnesses. A change in display will indicate location of fault. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

Bank 1 HO2S 1 & 2 Activity Test

Start and run engine until at normal operating temperature of 167-203°F (75-95°C).
On Tech 2 or equivalent scan tool, monitor HO2S 1 and 2 parameters in "Neutral" while using the scan tool IAC RPM control function to maintain a mass air flow of 10 grams/sec. Compare the amount of activity (frequency and amplitude) on Bank 1 HO2S 1 to the activity on Bank 1 HO2S 2 over a 30 second period.
If the amount of activity on Bank 1 HO2S 2 is nearly as great as the activity on Bank 1 HO2S 1, a problem exists. Use testing in DIAGNOSTIC PROCEDURE to find fault. If much less activity is noted on Bank 1 HO2S 2, system id functioning normally.

By using TECH 2 scan tool in TWC MONITOR TEST COUNTER mode TWC diagnostic test can be monitored. To complete TWC diagnostic test, counter must be allowed to count 49 samples and roll over to zero at least twice. A bad catalytic convertor will require 3 or more 50 sample tests to report failure.