Description Geo Storm I

Description

Diagnostic procedures used in this section are designed to find and repair SIR System problems. For best results, utilize diagnostic charts and follow sequence listed below.

1. Perform SIR DIAGNOSTIC SYSTEM CHECK. SIR DIAGNOSTIC SYSTEM CHECK should be starting point of any SIR diagnostics. SIR DIAGNOSTIC SYSTEM CHECK checks for proper INFLATABLE RESTRAINT indicator light operation and for SIR trouble codes.
2. Refer to proper diagnostic chart as directed by SIR DIAGNOSTIC SYSTEM CHECK. SIR DIAGNOSTIC SYSTEM CHECK will lead to correct chart to diagnose any SIR problem. By-passing these procedures may result in extended diagnostic time.
3. Repeat SIR DIAGNOSTIC SYSTEM CHECK after performing any repair or diagnostic procedures. Performing SIR DIAGNOSTIC SYSTEM CHECK after all repair or diagnostic procedures will ensure repair is correct and no other conditions exist.

When ignition switch is first turned on, system voltage is applied through SIR fuse to DERM at IGNITION 1 input and through IG fuse to DERM at SIR INDICATOR LOW output and SIR INDICATOR HIGH input. DERM responds by flashing INFLATABLE RESTRAINT indicator light 7 times. During this flashing, DERM is performing its diagnostic check of system.

When engine is being cranked, system voltage is applied to DERM at CRANK input. DERM grounds lamp circuit until system voltage is removed from CRANK input.

This results in a steady INFLATABLE RESTRAINT indicator light during cranking.

After engine is cranked, DERM will again flash INFLATABLE RESTRAINT indicator light 7 times.

Note. Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS .

1. INFLATABLE RESTRAINT indicator light should flash 7 times as ignition switch is turned to ON position. If indicator does not respond as described, use CHART C or CHART D to diagnose indicator malfunction.
2. As engine is cranked, INFLATABLE RESTRAINT indicator light should remain on steadily. If indicator does not respond as described, use CHART E to diagnose malfunction.
3. INFLATABLE RESTRAINT indicator light has completed BULB CHECK and remains on, indicating a current code has been detected. At this point, a Scan tool or INFLATABLE RESTRAINT indicator light can be used to diagnose malfunction. For FLASH CODE DIAGNOSIS, use CHART B.
4. After engine is cranked, INFLATABLE RESTRAINT indicator light should blink 7 times and then go out. If indicator begins to flash a Code 12, there is a system fault. Use CHART F to diagnose malfunction.
5. INFLATABLE RESTRAINT indicator light has completed BULB CHECK and is indicating no current codes exist.
6. Record all codes (both history and current) onto repair order. If there are no codes (history or current), record this fact onto repair order. No further diagnosis is necessary. If Scan tool indicates no data is being received from DERM, data link will require repair.
7. If multiple codes are displayed (history or current), order in which codes are diagnosed is very important. Refer to recommended charts.

Scheme 9

When ignition switch is first turned ON, system voltage is applied through IG fuse to SIR IGNITION INDICATOR HIGH B9 and to INFLATABLE RESTRAINT indicator light, which is connected to SIR INDICATOR LOW A1. SIR fuse also applies system voltage to IGNITION 1 inputs A3 and B3. DERM responds by flashing INFLATABLE RESTRAINT indicator light 7 times.

When engine is being cranked, system voltage is applied to DERM at CRANK input. DERM grounds lamp circuit until system voltage is removed from CRANK input. This results in a steady INFLATABLE RESTRAINT indicator light during cranking.

After engine is cranked, DERM will again flash INFLATABLE RESTRAINT indicator light 7 times.

Note. Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS .

1. DERM determines arming sensor is closed when system voltage or more is present at SENSE HI input and determines a discriminating sensor is closed when it notes low voltage at SENSE LOW input. Some faults may appear as an accident to DERM and record a Code 51. History Code 51 is not proof vehicle was in an accident.
2. Checks for intermittent electrical conditions within steering column.
3. Checks for intermittent shorts in 36VLR wiring (circuit No. 236).
4. Checks for incorrectly installed IG fuse and INFLATABLE RESTRAINT indicator light bulb or uncleared Code 61 after a completed wiring repair on circuit No. 39. Also checks for intermittent faults in circuits No. 688 and 358.
5. Checks for intermittent opens in ground path of deployment loop between base of steering column and both discriminating sensors (circuits No. 349 and 1003).
6. Checks for intermittent wiring shorts between 36VLR circuit No. 236, circuit No. 347 and circuit No. 349 of SIR wiring harness.

Scheme 10

When ignition switch is first turned ON, system voltage is applied through IG fuse to SIR INDICATOR HIGH (B9) and to INFLATABLE RESTRAINT indicator light, which is connected to SIR INDICATOR LOW (A1). SIR fuse also applies system voltage to IGNITION 1 inputs A3 and B3. DERM responds by flashing INFLATABLE RESTRAINT indicator light 7 times.

When engine is cranked, system voltage is applied to DERM at CRANK input. DERM grounds lamp circuit until system voltage is removed from CRANK input. This results in a steady INFLATABLE RESTRAINT indicator light during cranking.

After engine is cranked, DERM will again flash INFLATABLE RESTRAINT indicator light 7 times.

Note. Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS .

1. Checks for intermittent shorts to system voltage in 36VLR wiring (circuit No. 236).
2. Checks for intermittent shorts to ground in 36VLR wiring (circuit No. 236).
3. Checks for intermittent open in 36VLR wiring (circuit No. 236).
4. Checks for intermittent open in Force Hi and Force Low wiring (circuits No. 714 and 688).
5. Checks for intermittent opens or shorts to ground in SENSE LOW wiring (circuit No. 752).
6. Checks for shorts to system voltage in deployment loop (circuits No. 347 and 349) or in diagnostic circuits (circuits No. 347, 349, 688, 714, 752 and 753).
7. Checks for shorts between circuits No. 236 and 347 or 349.

Scheme 11

When ignition switch is first turned ON, system voltage is applied through IG fuse to SIR INDICATOR HIGH (B9) and to INFLATABLE RESTRAINT indicator light, which is connected to SIR INDICATOR LOW (A1). SIR fuse also applies system voltage to IGNITION 1 inputs A3 and B3. DERM responds by flashing INFLATABLE RESTRAINT indicator light 7 times.

When engine is being cranked, system voltage is applied to DERM at CRANK input. DERM grounds lamp circuit until system voltage is removed from CRANK input. This results in a steady INFLATABLE RESTRAINT indicator light during cranking.

After engine is cranked, DERM will again flash INFLATABLE RESTRAINT indicator light 7 times.

Note. Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS .

1. Checks for intermittent opens in 36VLR wiring (circuit No. 236).
2. Checks for intermittent open between IG fuse and arming sensor (circuit No. 39).

Scheme 12

When ignition switch is first turned ON, system voltage is applied through IG fuse to SIR INDICATOR HIGH (B9) and to INFLATABLE RESTRAINT indicator light, which is connected to SIR INDICATOR LOW (A1). SIR fuse also applies system voltage to IGNITION 1 inputs A3 and B3. DERM responds by flashing INFLATABLE RESTRAINT indicator light 7 times.

When engine is being cranked, system voltage is applied to DERM at CRANK input. DERM grounds lamp circuit until system voltage is removed from CRANK input. This results in a steady INFLATABLE RESTRAINT indicator light during cranking.

After engine is cranked, DERM will again flash INFLATABLE RESTRAINT indicator light 7 times.

Note. Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS .

1. If FLASH CODES have been used to diagnose and repair a fault, code(s) diagnosed and repaired will appear as history code only. Only way to clear history codes is with a Scan tool.
2. Where diagnostic charts request clearing of SIR codes, skip step since codes cannot be cleared through FLASH CODE diagnostics.

Scheme 13

When ignition switch is first turned ON, system voltage is applied through IG fuse to SIR INDICATOR LOW (A1). SIR fuse also applies system voltage to IGNITION 1 inputs A3 and B3. DERM responds by flashing INFLATABLE RESTRAINT indicator light 7 times.

Purpose of shorting bar is to turn INFLATABLE RESTRAINT indicator light on should DERM become disconnected.

When engine is being cranked, system voltage is applied to DERM at CRANK input. DERM grounds lamp circuit until system voltage is removed from CRANK input. This results in a steady INFLATABLE RESTRAINT indicator light during cranking.

After engine is cranked, DERM will again flash INFLATABLE RESTRAINT indicator light 7 times.

Note. Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS .

1. An open SIR fuse would result in a loss of IGNITION 1 voltage at DERM. DERM grounds lamp circuit (SIR INDICATOR LOW) whenever ignition switch is on.
2. If DERM and SIR harness connector are disconnected, shorting bar between terminals No. A1 and B1 of harness connector will ground lamp circuit.
3. Checks for a short to ground in IGNITION 1 circuits or DERM.
4. Checks for a short to ground on low side of lamp circuit external of DERM. SIR Load Tool prevents shorting bar in DERM connector from grounding lamp circuit.
5. Checks if short to ground is in DERM or IGNITION 1 circuits.
6. Checks for IGNITION 1 voltage at DERM. If IGNITION 1 circuits are open, DERM will ground lamp circuit whenever ignition switch is on (if SIR INDICATOR HIGH circuit is good).
7. Checks for a short to system voltage in CRANK circuit.

Scheme 14

When ignition switch is first turned on, system voltage is applied through SIR fuse and IG fuse to DERM at SIR INDICATOR LOW, SIR INDICATOR HIGH and IGNITION 1 inputs. DERM responds by flashing INFLATABLE RESTRAINT indicator light 7 times with a lamp driver at SIR INDICATOR LOW input.

When engine is being cranked, system voltage is applied to DERM at CRANK input. DERM grounds lamp circuit until system voltage is removed from CRANK input. This results in a steady INFLATABLE RESTRAINT indicator light during cranking.

After engine is cranked, DERM will again flash INFLATABLE RESTRAINT indicator light 7 times if ignition switch is on.

Note. Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS .

1. Checks if high side (power side) of lamp circuit is good. This circuit powers a number of indicators within indicators (such as SERVICE ENGINE SOON and OIL indicators). If these other indicators are operative, power supply to INFLATABLE RESTRAINT indicator light is okay.
2. When DERM is disconnected, shorting bar between terminals No. A1 and B1 of DERM harness connector should ground lamp circuit. If indicator does not illuminate, indicator circuit or shorting bar are suspect. If indicator comes on, DERM or SIR INDICATOR HIGH and IGNITION 1 circuits are suspect.
3. Checks IG fuse which is in high side (power side) of lamp circuit.
4. Checks for a short to ground in IG fuse circuits.
5. Checks for system voltage at IGNITION 1 and SIR INDICATOR HIGH inputs at DERM.
6. Checks if lamp circuit external to DERM is good.
7. Checks if ground circuits to DERM are good.

Scheme 15

When ignition switch is first turned on, system voltage is applied through IG fuse to SIR INDICATOR HIGH (B9) and to INFLATABLE RESTRAINT indicator light, which is connected to SIR INDICATOR LOW (A1). SIR fuse also applies system voltage to IGNITION 1 inputs A3 and B3. DERM responds by flashing INFLATABLE RESTRAINT indicator light 7 times.

When engine is cranked, system voltage is applied to DERM at CRANK input. DERM grounds lamp circuit until system voltage is removed from CRANK input. This results in a steady INFLATABLE RESTRAINT indicator light during cranking.

After engine is cranked, DERM will again flash INFLATABLE RESTRAINT indicator light 7 times if ignition switch is on.

Note. Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS .

1. Checks for system voltage at CRANK input of DERM during cranking.
2. Checks for an open or high resistance in CRANK circuit.

Scheme 16

When ignition switch is first turned on, system voltage is applied through IG fuse to SIR INDICATOR HIGH B9 and to INFLATABLE RESTRAINT indicator light, which is connected to SIR INDICATOR LOW A1. SIR fuse also applies system voltage to IGNITION 1 inputs A3 and B3. DERM responds by flashing INFLATABLE RESTRAINT indicator light 7 times.

When engine is being cranked, system voltage is applied to DERM at CRANK input. DERM grounds lamp circuit until system voltage is removed from CRANK input. This results in a steady INFLATABLE RESTRAINT indicator light during cranking.

After engine is cranked, DERM will again flash INFLATABLE RESTRAINT indicator light 7 times if ignition switch is on.

Note. Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS .

1. Checks DIAGNOSTIC REQUEST circuit for voltage at ALDL connector.
2. Checks if short to ground is in DIAGNOSTIC REQUEST circuit or DERM.

Scheme 17

DERM injects a current of 75 milliamperes through steering column from FORCE HI output (terminal No. A4) to FORCE LOW input (terminal No. A10). By monitoring voltage at SENSE HI input (terminal No. A7) and SENSE LOW input (terminal No. A6), DERM calculates combined resistance of inflator module, SIR coil, harness wiring (circuits No. 347 and 349) and connector terminal contact in steering column. Code 21 will set if resistance is greater than a specified value or 100-ohm resistor within resistor module is shorted.