1990 Honda Accord

Hi HONDAGUY90EX,

Is the Check Engine Lamp showing and what is the code?

Hi HONDAGUY90EX,

Lift up the carpet and check if the connector is tape to the wire harness near the kick panel. Should be a blue color 2 pin connector.

Hi HONDAGUY90EX,

CODE 31 - A/T FI SIGNAL B
1. Turn ignition off. Reset ECU by removing BACK-UP fuse in under-hood relay box for 10 seconds. Road test vehicle. Drive several miles so that transmission upshifts and downshifts several times. Verify if CHECK ENGINE light is on and if LED is flashing Code 31. If LED is flashing Code 31, go to next step. If LED is not flashing Code 31, problem is intermittent, system is okay at this time.
2. Turn ignition off. Connect ECU Test Harness between ECU and ECU connector. See Fig. 7 . Disconnect 22-wire connector from A/T control unit. Check for continuity between ECU terminal B4 and ground.
3. If continuity exists. repair short in Green wire between ECU terminal B4 and A/T control unit. If continuity did not exist. check for continuity on White/Red wire between ECU terminal B4 and A/T control unit connector.
4. If continuity does not exist, repair open in Green wire between ECU terminal B4 and A/T control unit. If continuity did exist, substitute a known good ECU. If condition is corrected, replace original ECU.

Hi HONDAGUY90EX,

The test harness is a special tool used for testing the ECU and its wiring. It is not necessary to have one.

I normally used a fine tipped test lamp and probe the ECU wire harness directly but care must be taken to avoid damaging the harness terminals.

Hi HONDAGUY90EX,

The explanation in my 3rd reply shows you how to diagnose and rectify the problem.

Hi HONDAGUY90EX.

When the S light blinks, it means an error has been detected by the transmission control module. Count the flashes and let me know.

DTC # 41 = HO2S sensor, a faoult in the sensor or circuit.
Most probably you need to replace it.

If the S light flashes 1 fast and ! Slow it means thers are 2 error codes.

DTC # 1 possible causes
1. Disconnected lock-up control solenoid valve A connector.
2. Short or open in lock-up control solenoid valve A wire.
3. Faulty lock-up control solenoid valve A.

DTC # 10 possible causes.
1. Disconnected water temperature sensor connector.
2. Short or open in water temperature sensor wire.
3. Faultry water temperature sensor.

Both symptoms causes the lock-up clutch not to engage. Idle speed is alos unstable if it is DTC # 1.

Hi,

The codes would be recycling and wait for the prolonged pause before you start counting. If it starts with a prolonged flash, count it as 10 and then the short pause with successive flashes are the intergers.

Prolonged flashes are the DTC separator.

Hi HONDAGUY90EX,

Have you resolved the DTC codes yet?

Possible causes for engine not able to rev pass 3,500 rpm.
1. Bad distributor.
2. Throttle Position Sensor bad or out of adjustment.
3. Faulty ECM.
4. Clogged/restricted exhaust passages.

When there are any DTC, you need to resolve them first. When they are resolved, other problems might go a way.