B1626 – PS Lap Pretensioner Squib Open

The Mitsubishi fault code B1626 – Passenger Seat Lap Pretensioner Squib Open Circuit is a manufacturer-specific diagnostic trouble code stored by the SRS (Supplemental Restraint System) airbag ECU on Mitsubishi vehicles. It indicates that the SRS control module has detected a complete break in the electrical circuit serving the squib (pyrotechnic initiator) of the passenger seat lap belt pretensioner. With B1626 active, the lap pretensioner cannot be guaranteed to fire in a collision event, leaving the front passenger without full seatbelt restraint protection. The SRS warning light will be continuously illuminated.

What Does B1626 Mean on a Mitsubishi?

Seatbelt pretensioners use a small pyrotechnic squib to instantly retract slack from the belt in a collision, locking the occupant firmly against the seat before airbag deployment. The SRS ECU continuously supplies a low-level monitoring current through each pretensioner squib circuit and compares the measured resistance against a tightly defined calibration window. B1626 is stored when the SRS ECU measures infinite or near-infinite resistance on the passenger seat lap pretensioner squib circuit — indicating a complete break in the circuit somewhere between the ECU and the pretensioner unit. As a result, the firing signal cannot reach the squib in a deployment event.

Symptoms of B1626

B1626 presents with the following indicators:

• SRS warning light continuously illuminated on the instrument cluster
• B1626 stored in the SRS/airbag ECU when scanned with MUT-III or compatible scanner
• Passenger seat lap pretensioner inoperative — will not fire in a collision event
• No driveability symptoms — B1626 is a purely electrical SRS fault
• Other SRS functions may remain operational, but the system is flagged as degraded
• Potential roadworthiness failure in markets where a permanently illuminated SRS warning light is a testable item

Common Causes of B1626

• Previously fired lap pretensioner squib — the most common cause; a pretensioner that activated in a prior collision has a severed squib circuit and must be replaced
• Corroded or unseated yellow SRS connector at the pretensioner — the shorting bar–equipped SRS connector under or beneath the passenger seat is exposed to moisture, dirt, and physical disturbance
• Broken, chafed, or pinched squib wiring harness — harness routed under the seat is vulnerable to damage from seat adjustment, seat removal during detailing or repair, and cable tie failure
• Failed pretensioner squib — internal open — the initiator element inside an unfired pretensioner can fail internally, particularly on older or high-mileage vehicles
• Corroded or spread SRS ECU connector pin — an open at the ECU end rather than at the pretensioner unit
• Improper seat removal and refitting — SRS harness connectors disconnected without following SRS disable protocol and not correctly reconnected
• Water ingress under the passenger seat — a common source of corrosion on the floor-level SRS harness connectors in this area

Common Misdiagnoses

• SRS ECU replaced without tracing the circuit: The ECU is rarely at fault for B1626. The open circuit is almost always in the pretensioner unit, the harness, or a connector. Full circuit isolation using a break-out box is required before any module replacement is considered.
• Squib circuit tested with a standard multimeter: Probing squib terminals with an unregulated DMM is a recognised deployment hazard. Only approved SRS break-out boxes and resistance simulators should be used for squib circuit measurement.
• Code cleared without repairing the open circuit: B1626 is a current fault actively monitored every ignition cycle. It returns immediately after clearing if the root cause has not been resolved.
• Connector reseated without inspecting for corrosion: Physically pushing a corroded connector back into place may temporarily restore continuity without reliably eliminating the open circuit. All SRS connector contacts must be inspected and cleaned before reconnection.
• Pretensioner assumed fired without visual confirmation: Always confirm whether the pretensioner has physically deployed before condemning it — an unfired pretensioner with an internal squib failure is a different repair to a post-collision unit replacement.

Affected Mitsubishi Vehicles

Model	Generation	Notes	Years
Outlander PHEV	GG/GF (1st Gen)	Dual pretensioner system on front seats; lap and shoulder monitored separately	2013–2021
Outlander PHEV	GN (2nd Gen)	Revised SRS architecture; same B1626 definition	2022–present
Outlander (non-PHEV)	GF/GG/ZJ/ZK/ZL	Lap pretensioner fitment confirmed across most market variants	2007–present
Eclipse Cross	GK/GL	Shares SRS module architecture with Outlander range	2017–present
ASX / RVR	GA/XD	Under-seat harness exposure common on higher-mileage examples	2010–present
Galant Fortis / Lancer	CY/CZ	Market-specific SRS configurations — verify pretensioner type before diagnosing	2007–2017

Tools & Equipment Required

Tool	Purpose	Notes
Mitsubishi MUT-III / MUT-IV	SRS scan, live data, code clear	Required to confirm B1626 and verify repair
SRS break-out box / squib resistance simulator	Safe squib circuit resistance measurement	Never use a standard DMM directly across squib terminals
Digital multimeter (DMM)	Harness continuity and voltage checks	Only for harness segments with SRS connectors fully disconnected and shorting bars engaged
Wiring diagram (OEM)	Identify B1626 squib circuit routing to passenger seat	Mitchell1 DIY or Mitsubishi FAST-II
Electrical contact cleaner & dielectric grease	SRS connector cleaning and corrosion prevention	Clean all yellow SRS connectors before reconnection
Trim and seat removal tools	Passenger seat removal for harness access	Torx and hex set; plastic trim tools to protect seat rail covers

Step-by-Step Diagnosis

• 1
  Disable the SRS System Before Any WorkSwitch off the ignition, remove the SRS fuse, and disconnect the battery negative terminal. Wait a minimum of 60 seconds before touching any SRS component, connector, or wiring. This allows the SRS backup capacitor to fully discharge and eliminates the risk of accidental pretensioner firing.
• 2
  Confirm B1626 with a Full SRS ScanReconnect power and use MUT-III or equivalent to read all stored SRS fault codes. Note whether B1626 is current or historical, and record any additional SRS codes that may indicate a shared wiring or connector fault affecting multiple circuits.
• 3
  Check for Prior Collision EvidenceBefore any electrical testing, inspect the passenger seat and B-pillar area for signs of previous collision damage or repair. A fired pretensioner has a visibly retracted and locked belt webbing that cannot be re-latched or pulled out. If the pretensioner has fired, replacement is the only repair.
• 4
  Inspect the Under-Seat SRS ConnectorWith SRS disabled, slide the passenger seat fully forward and inspect the yellow SRS connector(s) on the floor or seat frame. Check for corrosion, bent pins, moisture ingress, and incomplete seating. Ensure the secondary lock is fully engaged on each connector.
• 5
  Measure Squib Circuit Resistance with a Break-Out BoxConnect an approved SRS break-out box at the SRS ECU harness connector. Measure resistance on the passenger lap pretensioner squib circuit. An open (OL / infinite) reading with the pretensioner connected confirms a wiring open or internal squib failure. Disconnect the pretensioner connector and re-measure — if the open moves to the harness side, the wiring is at fault; if the circuit reads correctly with the pretensioner disconnected, the pretensioner squib has failed internally.
• 6
  Trace the Squib Harness if the Open is in the WiringRoute out the pretensioner squib harness from the seat area back toward the SRS ECU, checking all intermediate connectors, harness clips, and any areas where the cable may have been pinched under the seat rail or disturbed during a previous seat removal. Pay particular attention to the section of harness that flexes with seat adjustment.

Scanner Readout Explained

====================================================
  MITSUBISHI MUT-III SE — DIAGNOSTIC REPORT
====================================================
  Vehicle:     2018 Outlander PHEV (GG3W)
  Date:        2025-03-27  14:07:52
====================================================
MODULE: SRS / AIRBAG ECU
----------------------------------------------------
  B1626  Passenger Seat Lap Pretensioner Squib — Open Circuit
         Status:       Confirmed / Current
         Freeze Frame:
           Squib Circuit Resistance:   OL (open, no continuity)
           Expected Resistance Range:  2.0–3.0 Ω (typical squib spec)
           SRS Warning Lamp:          ON
====================================================
  LIVE DATA (SRS System Status)
====================================================
  Driver Front Airbag Squib:              OK
  Passenger Front Airbag Squib:           OK
  Driver Seatbelt Pretensioner Squib:     OK
  Passenger Lap Pretensioner Squib:       OPEN CIRCUIT — FAULT ACTIVE
  Passenger Shoulder Pretensioner Squib:  OK
  Side Curtain L Squib:                   OK
  Side Curtain R Squib:                   OK
====================================================
  NOTE: SRS system flagged as degraded.
  Passenger lap pretensioner deployment
  not guaranteed in collision event.
====================================================

Step-by-Step Repair Guide

Repair Path A: Passenger Lap Pretensioner Replacement

• 1
  Disable the SRS SystemRemove the SRS fuse and disconnect the battery negative terminal. Wait a minimum of 60 seconds before proceeding. Do not begin any pretensioner removal procedure until this wait period has fully elapsed.
• 2
  Remove the Passenger Seat if RequiredFor access to the lap pretensioner anchor point and squib connector, the passenger seat may need to be partially or fully removed depending on the model year. Refer to the workshop manual for the correct seat bolt torque values — these are safety-critical fasteners.
• 3
  Disconnect the Lap Pretensioner Squib ConnectorLocate the yellow SRS connector at the lap pretensioner. Press the secondary lock release and disconnect carefully. The integrated shorting bar will short the squib terminals on disconnection, preventing any residual current from reaching the squib during the repair.
• 4
  Remove and Dispose of the Faulty PretensionerUnbolt the lap pretensioner from its anchor point. Handle the unit carefully — even an unfired pretensioner is a live pyrotechnic device. Follow local regulations for disposal of pyrotechnic automotive components. Do not disassemble the unit.
• 5
  Fit the OEM Replacement PretensionerInstall the new OEM lap pretensioner and torque the anchor bolt to the workshop manual specification — pretensioner anchor torque is a safety-critical value. Reconnect the yellow SRS connector firmly until the secondary lock clicks fully into place.
• 6
  Re-enable SRS, Clear the Code & VerifyRefit the passenger seat to torque, reconnect the battery, and refit the SRS fuse. Use MUT-III to clear B1626 and run a full SRS system check. Confirm the SRS warning light extinguishes and that no further SRS codes are stored.

Repair Path B: SRS Harness Open Circuit Repair

• 1
  Isolate the Fault Location in the HarnessWith SRS disabled and using an approved break-out box, segment-test the squib harness to identify which section carries the open — from the pretensioner to the first intermediate connector, or from there to the SRS ECU. This narrows the physical search to a specific harness run.
• 2
  Locate and Repair the BreakCarefully trace the harness in the identified segment. Common damage points are where the harness flexes under the seat rail during adjustment, at routing clip edges, and at any point where previous work has disturbed the original cable routing. Repair using an OEM-specification SRS harness repair kit — confirm with the workshop manual whether splice repairs are permissible on this specific squib circuit.
• 3
  Verify Circuit Resistance, Re-enable SRS & ClearBefore refitting any trim or the seat, confirm the squib circuit resistance is within the specified window using the break-out box. Reconnect the battery and SRS fuse, clear B1626 with MUT-III, and confirm the SRS warning light extinguishes with no returning codes.

Repair Path C: SRS Connector Cleaning and Reseating

• 1
  Disable SRS & Access the Under-Seat ConnectorsFollow the full SRS disable procedure. Slide the passenger seat fully forward and rearward to expose all under-seat SRS connectors. Identify the yellow connector(s) serving the lap pretensioner squib circuit.
• 2
  Clean the Connector ContactsDisconnect the affected SRS connector carefully. Inspect both male and female pins for corrosion, green oxidation, or moisture residue. Apply electrical contact cleaner and allow to dry fully. Apply a light coat of dielectric grease to the pin faces before reconnection.
• 3
  Reseat, Verify & ClearReconnect the SRS connector firmly — the secondary lock must click fully into position. Use a break-out box to confirm squib circuit resistance is within specification before re-enabling the SRS system. Clear B1626 with MUT-III and confirm the warning light extinguishes.

Repair Cost Estimates

Repair	Parts Cost (est.)	Labour (est.)	Total (est.)	DIY Difficulty
SRS connector cleaning & reseating	€0–€10	0.5 hr	€0–€60	Medium — SRS safety protocols required
SRS harness open circuit repair	€10–€50	1–3 hr	€60–€260	Hard — requires SRS break-out box and wiring expertise
Passenger lap pretensioner replacement (OEM)	€80–€250	1–2 hr	€130–€370	Hard — SRS specialist recommended
SRS ECU connector pin repair	€5–€30	1–2 hr	€55–€200	Hard — requires SRS break-out box

Prevention & Maintenance Tips

• Follow the full SRS disable procedure whenever removing the passenger seat — the under-seat SRS harness is the most common point of disturbance-related B1626 faults
• Inspect under-seat SRS connectors for moisture and corrosion at every major service — floor-level SRS connectors are exposed to water ingress from wet footwear and car washing
• Never route cables or fit accessories under the passenger seat without checking SRS harness clearance — pinched squib wiring is a direct cause of B1626
• Use OEM or OEM-equivalent pretensioner units only — aftermarket units may not meet the squib resistance specification monitored by the SRS ECU
• Always clear and verify SRS codes after any seat, carpet, or dashboard repair — an illuminated SRS warning light after unrelated interior work is a common post-service complaint with a straightforward cause
• Address the SRS warning light promptly — a degraded SRS system cannot be relied on to provide full occupant protection in a collision

Frequently Asked Questions

Can I drive my Mitsubishi with B1626 stored?

The vehicle remains driveable, but the passenger lap pretensioner cannot be guaranteed to fire in a collision. The front passenger is at increased risk of injury in a significant impact. In many markets a permanently illuminated SRS warning light is also a roadworthiness failure point. The fault should be diagnosed and repaired as soon as possible.

Will B1626 clear itself after a connector is reseated?

No. B1626 is stored in SRS ECU memory and must be actively cleared using a compatible scanner such as MUT-III. Even after the open circuit is fully repaired and the squib circuit resistance is confirmed within specification, the code and SRS warning light will remain until cleared with a scan tool.

Can I test the pretensioner squib with my multimeter?

No. Using a standard digital multimeter directly across squib terminals is a recognised pretensioner deployment hazard. Even the small current from a DMM ohms function can theoretically fire the squib. Only an approved SRS squib resistance simulator or a dedicated SRS break-out box should be used for any squib circuit resistance measurement.

How do I know if the lap pretensioner has already fired?

A fired lap pretensioner will have a fully retracted belt that locks completely and cannot be pulled out or re-latched. The pretensioner mechanism will also typically show physical evidence of gas discharge. If the belt operates normally but B1626 is present, the pretensioner has not fired and the fault is electrical — either an internal squib failure, a wiring open, or a connector issue.

Is B1626 likely to appear after a seat has been removed and refitted?

Yes — this is one of the most common triggers for B1626. If the passenger seat was removed during a carpet replacement, detailing, or repair and the SRS harness connectors were disconnected without following the correct SRS disable procedure, or were not fully reseated on refitting, B1626 will be stored on the next ignition cycle. Always inspect under-seat SRS connectors after any seat removal work.

Can an aftermarket pretensioner be used for the repair?

Aftermarket pretensioner units carry significant risk on SRS systems. The squib resistance specification is narrow and type-specific — an incorrectly specced unit may generate a new fault code immediately or may not perform to OEM deployment standards in a collision. OEM or OEM-equivalent parts are strongly recommended for all pretensioner replacements.

Does the SRS ECU need replacing if B1626 returns after a new pretensioner is fitted?

Only after thorough circuit tracing has confirmed continuity throughout the entire squib harness from the pretensioner connector all the way to the SRS ECU connector pins with no open detected anywhere. Corroded or spread pins at the ECU connector are a more common cause of a persistent open than an internal ECU failure, and should be inspected carefully before any module is condemned.

How long does a passenger lap pretensioner replacement typically take?

For a technician with the correct workshop manual and tools, the repair typically takes one to two hours, with the majority of that time spent on seat removal, access, and refitting. Code clearing and SRS system verification with MUT-III adds a further 15–20 minutes.

Conclusion

Mitsubishi B1626 – Passenger Seat Lap Pretensioner Squib Open Circuit is a high-severity SRS fault that disables the passenger lap pretensioner and must be diagnosed and repaired without delay. The most common causes are a previously fired pretensioner, a corroded or unseated under-seat SRS connector, or a wiring open introduced during seat removal work. Always follow the full SRS disable procedure before working on any component, use an approved break-out box to isolate whether the open is in the pretensioner or the harness, replace faulty components with OEM units, and verify and clear with MUT-III after repair.