KOER Self-Test

1) DO NOT enter this test sequence until a Code 11 or 111 (pass code) has been retrieved in KOEO SELF-TEST. If system has not passed KOEO SELF-TEST, code recorded in KOER SELF-TEST may not be valid.

2) Deactivate self-test by removing and reconnecting jumper wire, or by procedure specified by test equipment in use. Start engine, and run it for 2 minutes at 2000 RPM to warm-up Heated Exhaust Gas Oxygen (HEGO) sensor. Turn engine off, and wait 10 seconds. Activate KOER SELF-TEST using a jumper wire or appropriate procedure for test equipment used. Start engine. Record all service codes displayed. Check following items:

If engine starts and stalls, or stalls during self-test, go to TEST S .
If vehicle is equipped with a Brake On-Off (BOO) switch, brake pedal must be depressed and released after ID code portion of test.
When Dynamic Response Code appears, perform a brief Wide Open Throttle (WOT). DO NOT perform WOT unless requested.
If Code 98 or 998 is displayed, EEC-IV system is operating in Failure Management Effects Mode (FMEM). Vehicle has not passed KOEO SELF-TEST and cannot be diagnosed while in FMEM mode. Rerun KOEO SELF-TEST.
If KOER codes are present, refer to appropriate CIRCUIT TEST listed in KOER SELF-TEST CODE REFERENCE table. If system will not output codes, go to TEST QA.

KOER SELF-TEST CODE REFERENCE

Service Code

Circuit Test & Step No.

114

TEST DA , Step 1)

116

TEST DA , Step 1)

121

TEST DH , Step 2)

126

TEST DF , Step 1)

129

TEST DC , Step 10)

136

TEST H , Step 14)

137

TEST H , Step 23)

159

TEST DC , Step 1)

167

TEST DH , Step 20)

172

TEST H , Step 1)

173

TEST H , Step 1)

213

TEST P , Step 1)

411

TEST KE , Step 15)

412

TEST KE , Step 1)

511

⁽¹⁾

513

⁽¹⁾

536

TEST FD , Step 1)

538

TEST M , Step 1)

998

⁽²⁾

No Codes Or Codes Not Listed

TEST QA , Step 1)

⁽¹⁾	Replace ECA.

⁽²⁾	Perform KOEO SELF-TEST.