P1684 Jeep OBD Code Diagnostic Procedure

P1684 Jeep OBD Code

BATTERY WAS DISCONNECTED

For a complete wiring diagram Refer to Section 8W.

Theory of Operation

Note: This is not a fault code. It exists to provide reference information only. A battery backed RAM is used to maintain some learned values. When the battery is disconnected, this memory
is lost. When the battery is reconnected, the loss of learned values will be detected by the controller. The code will be set and the learned values will be initialized to known constants and the learning
process will continue. Setting the code has no effect except for re-initialization of learned values.

When Monitored:

After a reset (ignition key turned to the RUN position).

Set Condition:The checksum of the battery backed RAM does not match the stored checksum. Set Time: Less than 7 ms.

Possible Causes

BATTERY WAS DISCONNECTED

PCM WAS REPLACED OR DISCONNECTED

QUICK LEARN WAS PERFORMED

(A919) FUSED B+ CIRCUIT TO PCM OPEN

(Z908 and Z977) GROUND CIRCUIT OPEN

Always perform the 42RLE Pre-Diagnostic Troubleshooting procedure before proceeding.

(Refer to 21 – TRANSMISSION/TRANSAXLE/AUTOMATIC- 42RLE – STANDARD PROCEDURE)

Diagnostic Test

1. BATTERY WAS DISCONNECTED

Has the battery been disconnected, lost its charge, or been replaced recently?

Yes

Disconnecting or replacing the battery will set this DTC. Erase the DTC.

Perform 42RLE TRANSMISSION VERIFICATION TEST(Refer to 21 – TRANSMISSION/TRANSAXLE/AUTOMATIC – 42RLE – STANDARD PROCEDURE)

Go To 2

2. CHECK IF THE QUICK LEARN WAS PERFORMED

Has a Quick Learn procedure been performed?
Yes

Performing Quick Learn will set this DTC. Erase the DTC.

Perform 42RLE TRANSMISSION VERIFICATION TEST(Refer to 21 – TRANSMISSION/TRANSAXLE/AUTOMATIC – 42RLE – STANDARD PROCEDURE)

Go To 3

3. PCM REPLACED OR DISCONNECTED

Has the PCM been replaced or disconnected?

Yes

Replacing or disconnecting the PCM will set this DTC. Erase the DTC.

Perform 42RLE TRANSMISSION VERIFICATION TEST(Refer to 21 – TRANSMISSION/TRANSAXLE/AUTOMATIC – 42RLE – STANDARD PROCEDURE)

Go To 4

4. (A919) FUSED B(+) CIRCUIT

Turn the ignition off to the lock position.

Disconnect the PCM C1 harness connector.

NOTE:
Check connectors – Clean/repair as necessary.

CAUTION:
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller
Special Tool #8815 to perform diagnosis.

Using a 12-volt test light connected to ground, check the (A919) Fused B(+) circuit.

NOTE:
The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

Go To 5

Repair the Fused B+ circuit for an open. If the fuse is open make sure to check for a short to ground.

Perform 42RLE TRANSMISSION VERIFICATION TEST(Refer to 21 – TRANSMISSION/TRANSAXLE/AUTOMATIC – 42RLE – STANDARD PROCEDURE)

5. (Z908) AND (Z977) GROUND CIRCUITS

Turn the ignition off to the lock position.

Disconnect the PCM C4 harness connector.

NOTE:
Check connectors – Clean/repair as necessary.

Using a 12-volt test light connected to 12-volts, check the (Z908) and (Z977) Ground circuits in the appropriate terminal of Miller tool #8815.

NOTE:
The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly for all of the ground circuits?

Yes

Go To 6

Repair the Ground circuits for an open.

Perform 42RLE TRANSMISSION VERIFICATION TEST(Refer to 21 – TRANSMISSION/TRANSAXLE/AUTOMATIC – 42RLE – STANDARD PROCEDURE)

6. INTERMITTENT WIRING AND CONNECTORS

The conditions necessary to set the DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorted and open circuits.
With the scan tool, check the DTC EVENT DATA to help identify the conditions in which the DTC was set.

Were there any problems found?

Yes

Repair as necessary.

Perform 42RLE TRANSMISSION VERIFICATION TEST(Refer to 21 – TRANSMISSION/TRANSAXLE/AUTOMATIC – 42RLE – STANDARD PROCEDURE)

Test Complete.