DTC 56

DTC 56: "N" Range Light System

Part 1 Of 2:

Part 2 Of 2:

CIRCUIT OPERATION
If a fail-safe is triggered while driving forward, the PCM flashes the "N" range light once per second (triggered fail-safe). The PCM does this by switching battery positive voltage to terminal 121.

DTC SET CONDITIONS
If the PCM detects a fail-safe condition, it will attempt to illuminate the "N" range light. The PCM sends a 12 volts pulse for 60 - 180 ms. If it does not detect a voltage drop during the pulse, it waits about 60 seconds and pulses 12 volts again for 60 - 180 ms. If the PCM does no detect the voltage drop before the ignition switch is turned "LOCK" (OFF), the PCM will consider it as an short circuit of the "N" range light circuit and DTC 56 is set.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
^ Defective "N" range light bulb
^ Damaged harness or connector
^ Malfunction of the PCM

DIAGNOSIS

Required Special Tool:
^ MB991958: Scan Tool (MUT-III Sub Assembly)
^ MB991824: V.C.I.
^ MB991827: MUT-III USB Cable
^ MB991911: MUT-III Main Harness B

STEP 1. Check the "N" range light bulb.
1) Turn the ignition switch to the "ON" position.
2) Move the selector lever to "N" position.
^ The "N" range light in the combination meter illuminates.
3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Does the "N" range light illuminate?
YES: Go to Step 7.
NO: Go to Step 2.

STEP 2. Check the "N" range light bulb.
1) Remove the combination meter.
2) Check the "N" range light bulb.
Q: Is the bulb in good condition?
YES: Go to Step 3.
NO: Replace the "N" range light bulb.

STEP 3. Check combination meter connector C-43 for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q: Are the connector and terminals in good condition?
YES: Go to Step 4.
NO: Repair or replace the damaged components.

STEP 4. Measure the resistance at combination meter connector C-43.





1) Disconnect connector C-43 and measure at the harness side.





2) Measure the resistance between terminal 12 and ground.
^ The measured resistance should be less than 2 ohms.
Q: Is the measured resistance less than 2 ohms?
YES: Go to Step 7.
NO: Go to Step 5.

STEP 5. Check joint connector (2) connector C-78 for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q: Are the connector and terminals in good condition?
YES: Go to Step 6.
NO: Repair or replace the damaged components.

STEP 6. Check the harness for open circuit or damage between combination meter connector C-43 terminal 12 and body ground.





Q: Is the harness wire in good condition?]
YES: Go to Step 7.
NO: Repair or replace the harness wire.

STEP 7. Check transmission range switch connector B-41, combination meter connector C-43, intermediate connector C-27 and PCM connector C-61 <2.4L Engine> or C-63 <3.0L Engine> for loose, corroded or damaged terminals, or terminals pushed back in the connector.














Q: Are the connectors and terminals in good condition?
YES: Go to Step 8.
NO: Repair or replace the damaged components.

STEP 8. Check the harness for open circuit, short circuit to ground and damage between combination meter connector C-43 terminal 9 and PCM connector C-61 <2.4L Engine> or C-63 <3.0L Engine> terminal 121.








Q: Is the harness wire in good condition?
YES: Go to Step 9.
NO: Repair or replace the harness wire.

STEP 9. Using scan tool MB991958, read the A/T diagnostic trouble code.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.





1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the "ON" position.
3) Check for A/T diagnostic trouble code.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC 56 set?
YES: Replace the PCM.
NO: The procedure is complete.