2001-2004 Models

NOTE:

Record all freeze data and review General Troubleshooting Information (see GENERAL TROUBLESHOOTING INFORMATION ) before you troubleshoot.
This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.

Turn the ignition switch ON (II).
Check whether the scan tool or the HDS indicates code for the throttle position (TP) sensor.
Does the scan tool or the HDS indicate code for TP sensor?
1. YES -Do the DTC Troubleshooting for the TP sensor circuit low voltage (see DTC P0122: TP SENSOR CIRCUIT LOW VOLTAGE ), and the TP sensor circuit high voltage (see DTC P0123: TP SENSOR CIRCUIT HIGH VOLTAGE ). Recheck for DTC P1790 after troubleshooting.
2. NO -Turn the ignition switch OFF, then go to step 3.
Disconnect TCM connectors A (26P) and B (22P).
Turn the ignition switch ON (II).
Measure the voltage between TCM connector terminals B20 and A4.

Fig 1: Measuring Voltage Between TCM Connector Terminals B20 And A4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 5 V?
1. YES -Go to step 6.
2. NO -Repair an open or short in VREF wire between TCM connector terminals B20 and the ECM.
Close the throttle fully.
Measure the voltage between TCM connector terminals B4 and A4.

Fig 2: Measuring Voltage Between TCM Connector Terminals B4 And A4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 0.5 V?
1. YES -Check for loose terminal fit in the TCM connectors. If necessary, substitute a known-good TCM (see HOW TO TROUBLESHOOT CIRCUIT AT THE TCM ) and recheck.
2. NO -Repair an open or short in the wire between TCM connector terminal B4 and the TP sensor.