Code
P1696
CHRYSLER
P — Powertrain
PCM Failure EEPROM Write Denied
Views:
UK: 22
EN: 43
RU: 51
AI status
Completed
Completed
100%
Causes
- Low or unstable battery/charging system voltage during programming or operation
- Poor power/ground connections to PCM
- Corrupted or failing PCM EEPROM or processor
- Failed or interrupted PCM reflash/programming attempt
- CAN/serial communication faults or wiring damage
- Immobilizer/security module or VIN mismatch preventing writes
Symptoms
- MIL (Check Engine Light) illuminated
- Stored PCM-related DTCs and/or multiple communication or memory codes
- Vehicle may enter limp mode, run poorly, or fail to start depending on module function
- Loss of learned adaptations or stored settings (idle, transmission shifts, learned fuel trims)
- Failed reprogramming attempts reported by scan tool
What to check
- Retrieve all stored DTCs and freeze frame data with a capable scan tool; record before clearing
- Check battery voltage (with key ON) and state of charge; ensure battery is charged and terminals clean/tight
- Inspect PCM power and ground connections, fuses and fusible links for corrosion or damage
- Check for water intrusion or physical damage at PCM and connectors
- Verify scan tool can communicate reliably with PCM; check for additional communication codes (CAN bus U‑codes)
- Confirm vehicle security/immobilizer status and that correct dealer-level procedures are used for reprogramming
Signal parameters
- Battery voltage (key ON, engine OFF): ideally >12.4 V before programming
- Cranking voltage: should not drop below ~9–10 V during starter engagement
- CAN bus idle voltages: CAN_H ~2.5 V, CAN_L ~2.5 V (differential ~0 V idle) — check for bus continuity and no short to battery/ground
- PCM supply voltages: B+ on PCM power pins present and stable during tests
- PCM ground resistance: low ohm continuity to chassis ground
Diagnostic algorithm
- Capture and note all DTCs, freeze frame and occurrence count. Do not rely on a single clear attempt.
- Verify battery state of charge and charging system; charge or replace battery if voltage or capacity is marginal.
- Visually inspect PCM connectors, harness, fuses, and grounds for corrosion, loose pins, or water damage; repair any defects.
- Check vehicle data bus communication with a manufacturer‑level scan tool; confirm no CAN/U‑codes are present and communication is stable.
- If communication intermittency is found, trace/repair wiring and connectors between PCM and network until stable.
- Attempt to clear the code and perform a key cycle; if P1696 returns immediately, suspect persistent module or memory fault.
- If recent programming was attempted, verify the correct software file and programming procedure were used; consult manufacturer TSBs and reflash instructions.
- Attempt a controlled reprogram/reflash using approved dealer/consultant tools and stable battery power (use battery maintainer or jumper pack per manufacturer guidelines).
- If reflash fails repeatedly and wiring/power/communication have been confirmed good, consider PCM replacement and program the new unit with correct calibrations and VIN. Retest.
- After repair or reprogramming, erase codes and perform a road test and recheck for reoccurrence; if code returns, escalate to manufacturer‑level support.
Likely causes
- Low battery voltage or poor battery/ground connections during a programming attempt
- Corrupted EEPROM or failed PCM hardware after a failed reflash
- Communication fault on vehicle data bus (CAN/serial) preventing proper write confirmation
Fault status
Status
PCM EEPROM write operation denied — non‑volatile memory write failed or was rejected. Investigate power, communications, programming procedure and PCM hardware.
Repair difficulty: Hard
Diagnostic time: 1.0 - 3.0 hours
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