DTC 23

DTC 23: Engine Speed Signal Circuit

NOTE:
^ If the MIL indicator is ON, troubleshoot the PGM-FI system first.
^ Even though the system is operating normally, the EPS indicator will come on under the following conditions.

Condition 1:
^ The vehicle was traveling at least 12.4 mph (20 km/h), then
^ A rapid change in vehicle speed was detected, then
^ The vehicle (or the vehicle speed sensor signal) stopped for at least 5 seconds, and
^ The engine speed was still 1,640 rpm or higher for at least 5 seconds

Condition 2:
After the vehicle (or the vehicle speed sensor signal) has stopped for at least 10 seconds, yet the engine speed was still 1,640 rpm or higher for at least 20 seconds.

Condition 3:
When the vehicle speed is 6.2 mph (10 km/h) or above and the engine is running at 280 rpm or below for 3 seconds.

1. Start the engine and check the tachometer.
Is the tachometer working correctly?
YES-Go to step 2.
NO-Perform the tachometer system troubleshooting.
2. Test-drive the vehicle above 9.3 mph (15 km/h).
Is the speedometer working correctly?
YES-Go to step 3.
NO-Perform the speedometer system troubleshooting.
3. Block the rear wheels-and raise the vehicle, and support it with safety stands in the proper locations.
4. Turn the ignition switch ON (II).





5. Block the right front wheel, and slowly rotate the left front wheel, and measure the voltage between EPS control unit connector C (20P) terminal No. 7 and body ground.
Does the voltage pulse between 0 V and 5 V?
YES-Go to step 6.
NO-Repair open in the wire between the EPS control unit and the VSS. If the wire is OK, check for a loose or poor connections at the EPS control unit. If necessary, substitute a known-good EPS control unit, and rechecked
6. Turn the ignition switch OFF, and disconnect EPS control unit connector C (20P).
7. Start the engine, and let it idle.





8. Measure the voltage between EPS control unit connector C (20P) terminal No.19 and body ground.
Is there about 6 V at idle? (With the meter set for frequency, is there 33 Hz per 1,000 engine rpm?)
YES-Check for loose EPS control unit connectors. If necessary, substitute a known-good EPS control unit and recheck.
NO-Repair open in the wire between the EPS control unit and the ECM.