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Home / DTC / B1021 — Driver Deployment Loop Resistance High

B1021 — Driver Deployment Loop Resistance High

Detailed page for trouble code B1021.

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Code

B1021

HUMMER B — Body

Driver Deployment Loop Resistance High

Brand: HUMMER
Type: B — Body
Views: UK: 17 EN: 42 RU: 23
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged or corroded connector at driver airbag module or clock spring
  • Worn, pinched, or broken wiring in the steering column or harness
  • Faulty/aged clock spring (spiral cable)
  • Defective driver-side airbag module (squib) with increased internal resistance
  • Poor crimps or damaged terminals
  • Previous crash damage or improper repairs affecting the SRS circuit

Symptoms

  • SRS / airbag warning lamp illuminated on instrument cluster
  • Potential disablement of driver airbag deployment
  • Possible intermittent SRS faults that return after clearing codes
  • No other drivability symptoms (engine runs normally)

What to check

  • Scan for SRS codes and note freeze frame and status bits
  • Verify battery voltage is stable and no low-voltage events occurred
  • Inspect steering wheel/column area for aftermarket equipment or damage
  • Visually inspect connectors and wiring at the driver airbag, clock spring, and under-dash harness
  • Check vehicle history for previous collisions or airbag deployment
  • Confirm airbag lamp operation and whether other SRS codes are present

Signal parameters

  • Expected driver squib loop: low single-digit ohms (consult OEM service manual for exact spec).
  • Open circuit (OL/infinite) indicates broken wiring or disconnected connector.
  • High resistance relative to spec (value above manufacturer threshold) triggers B1021.
  • With ignition OFF and battery disconnected, continuity/ohms checks can be made across squib pins — never measure resistance with airbag connected to diagnostic voltage.
  • Airbag lamp: ON when the control module detects loop resistance out of range

Diagnostic algorithm

  1. Safety first: disable SRS power. Disconnect negative battery terminal and wait the manufacturer-specified time (typically several minutes) before any airbag circuit work.
  2. Read and record all SRS codes, then clear codes and attempt to re-run to confirm persistence.
  3. Perform visual inspection of steering wheel, clock spring cover, and under-dash harness for damaged wires, pinched areas, or loose/corroded connectors.
  4. With battery still disconnected, disconnect the driver airbag connector and measure resistance across the squib pins using a digital multimeter; compare to OEM specification. Note: do not attempt to deploy the squib for testing.
  5. Check continuity and resistance across the circuit from the airbag connector back to the SRS control module connector; isolate where resistance increases or opens.
  6. If resistance is high at the clock spring, remove steering wheel per service manual and test/remove the clock spring for bench testing or replacement.
  7. If clock spring tests good, inspect/replace any damaged wiring or connectors, repair crimps or terminals as necessary, then reassemble and clear codes.
  8. After repairs, reconnect battery, retrieve codes, perform SRS system self-test, and verify that the airbag lamp extinguishes and B1021 does not return. If fault returns, follow module-level diagnostic procedures or consult dealer-level service information.

Likely causes

  • Clock spring internal breakage or corrosion causing intermittent/high resistance
  • Corroded/contaminated connector under the steering wheel or at airbag module
  • Wire insulation chafed in steering column causing partial short/high resistance
  • Airbag module with degraded squib resistance due to age or contamination

Fault status

⚠️ Status
Driver Deployment Loop Resistance High — SRS control module detected higher-than-allowed resistance in the driver airbag deployment circuit; driver airbag may be disabled.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-3 hours

Similar codes

B1020 B1022 B1010 B1000 B1060
Repair manuals

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138

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Code

B1021

LAND ROVER B — Body

Power switch

Brand: LAND ROVER
Type: B — Body
Views: UK: 18 EN: 40 RU: 21
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged or corroded connector at driver airbag module or clock spring
  • Worn, pinched, or broken wiring in the steering column or harness
  • Faulty/aged clock spring (spiral cable)
  • Defective driver-side airbag module (squib) with increased internal resistance
  • Poor crimps or damaged terminals
  • Previous crash damage or improper repairs affecting the SRS circuit

Symptoms

  • SRS / airbag warning lamp illuminated on instrument cluster
  • Potential disablement of driver airbag deployment
  • Possible intermittent SRS faults that return after clearing codes
  • No other drivability symptoms (engine runs normally)

What to check

  • Scan for SRS codes and note freeze frame and status bits
  • Verify battery voltage is stable and no low-voltage events occurred
  • Inspect steering wheel/column area for aftermarket equipment or damage
  • Visually inspect connectors and wiring at the driver airbag, clock spring, and under-dash harness
  • Check vehicle history for previous collisions or airbag deployment
  • Confirm airbag lamp operation and whether other SRS codes are present

Signal parameters

  • Expected driver squib loop: low single-digit ohms (consult OEM service manual for exact spec).
  • Open circuit (OL/infinite) indicates broken wiring or disconnected connector.
  • High resistance relative to spec (value above manufacturer threshold) triggers B1021.
  • With ignition OFF and battery disconnected, continuity/ohms checks can be made across squib pins — never measure resistance with airbag connected to diagnostic voltage.
  • Airbag lamp: ON when the control module detects loop resistance out of range

Diagnostic algorithm

  1. Safety first: disable SRS power. Disconnect negative battery terminal and wait the manufacturer-specified time (typically several minutes) before any airbag circuit work.
  2. Read and record all SRS codes, then clear codes and attempt to re-run to confirm persistence.
  3. Perform visual inspection of steering wheel, clock spring cover, and under-dash harness for damaged wires, pinched areas, or loose/corroded connectors.
  4. With battery still disconnected, disconnect the driver airbag connector and measure resistance across the squib pins using a digital multimeter; compare to OEM specification. Note: do not attempt to deploy the squib for testing.
  5. Check continuity and resistance across the circuit from the airbag connector back to the SRS control module connector; isolate where resistance increases or opens.
  6. If resistance is high at the clock spring, remove steering wheel per service manual and test/remove the clock spring for bench testing or replacement.
  7. If clock spring tests good, inspect/replace any damaged wiring or connectors, repair crimps or terminals as necessary, then reassemble and clear codes.
  8. After repairs, reconnect battery, retrieve codes, perform SRS system self-test, and verify that the airbag lamp extinguishes and B1021 does not return. If fault returns, follow module-level diagnostic procedures or consult dealer-level service information.

Likely causes

  • Clock spring internal breakage or corrosion causing intermittent/high resistance
  • Corroded/contaminated connector under the steering wheel or at airbag module
  • Wire insulation chafed in steering column causing partial short/high resistance
  • Airbag module with degraded squib resistance due to age or contamination

Fault status

⚠️ Status
Driver Deployment Loop Resistance High — SRS control module detected higher-than-allowed resistance in the driver airbag deployment circuit; driver airbag may be disabled.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-3 hours

Similar codes

B1020 B1022 B1010 B1000 B1060
320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

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Code

B1021

MITSUBISHI B — Body

Air thermo sensor low

Brand: MITSUBISHI
Type: B — Body
Views: UK: 18 EN: 43 RU: 24
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged or corroded connector at driver airbag module or clock spring
  • Worn, pinched, or broken wiring in the steering column or harness
  • Faulty/aged clock spring (spiral cable)
  • Defective driver-side airbag module (squib) with increased internal resistance
  • Poor crimps or damaged terminals
  • Previous crash damage or improper repairs affecting the SRS circuit

Symptoms

  • SRS / airbag warning lamp illuminated on instrument cluster
  • Potential disablement of driver airbag deployment
  • Possible intermittent SRS faults that return after clearing codes
  • No other drivability symptoms (engine runs normally)

What to check

  • Scan for SRS codes and note freeze frame and status bits
  • Verify battery voltage is stable and no low-voltage events occurred
  • Inspect steering wheel/column area for aftermarket equipment or damage
  • Visually inspect connectors and wiring at the driver airbag, clock spring, and under-dash harness
  • Check vehicle history for previous collisions or airbag deployment
  • Confirm airbag lamp operation and whether other SRS codes are present

Signal parameters

  • Expected driver squib loop: low single-digit ohms (consult OEM service manual for exact spec).
  • Open circuit (OL/infinite) indicates broken wiring or disconnected connector.
  • High resistance relative to spec (value above manufacturer threshold) triggers B1021.
  • With ignition OFF and battery disconnected, continuity/ohms checks can be made across squib pins — never measure resistance with airbag connected to diagnostic voltage.
  • Airbag lamp: ON when the control module detects loop resistance out of range

Diagnostic algorithm

  1. Safety first: disable SRS power. Disconnect negative battery terminal and wait the manufacturer-specified time (typically several minutes) before any airbag circuit work.
  2. Read and record all SRS codes, then clear codes and attempt to re-run to confirm persistence.
  3. Perform visual inspection of steering wheel, clock spring cover, and under-dash harness for damaged wires, pinched areas, or loose/corroded connectors.
  4. With battery still disconnected, disconnect the driver airbag connector and measure resistance across the squib pins using a digital multimeter; compare to OEM specification. Note: do not attempt to deploy the squib for testing.
  5. Check continuity and resistance across the circuit from the airbag connector back to the SRS control module connector; isolate where resistance increases or opens.
  6. If resistance is high at the clock spring, remove steering wheel per service manual and test/remove the clock spring for bench testing or replacement.
  7. If clock spring tests good, inspect/replace any damaged wiring or connectors, repair crimps or terminals as necessary, then reassemble and clear codes.
  8. After repairs, reconnect battery, retrieve codes, perform SRS system self-test, and verify that the airbag lamp extinguishes and B1021 does not return. If fault returns, follow module-level diagnostic procedures or consult dealer-level service information.

Likely causes

  • Clock spring internal breakage or corrosion causing intermittent/high resistance
  • Corroded/contaminated connector under the steering wheel or at airbag module
  • Wire insulation chafed in steering column causing partial short/high resistance
  • Airbag module with degraded squib resistance due to age or contamination

Fault status

⚠️ Status
Driver Deployment Loop Resistance High — SRS control module detected higher-than-allowed resistance in the driver airbag deployment circuit; driver airbag may be disabled.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-3 hours

Similar codes

B1020 B1022 B1010 B1000 B1060
406

Browse 406 MITSUBISHI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

MITSUBISHI

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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

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