Skip to main content
Home / Diagnostics / Test Library / Parasitic Draw
Current diagnostic step
2002 · EXACT TEST

2002 Firebird Parasitic-Draw Test

Applies to: 2002 Firebird / Trans Am with the LS1, unless a step below says otherwise.

This is the actual current-measurement portion of the parked-battery diagnosis. Prove the battery and charging system before doing it.

PAGE SCOPELS12002Use this page only for the model-year/application stated here unless another year is explicitly identified in the published material.

Start here

Perform this test exactly as shown, record the result, then use PASS or FAIL to return to the diagnostic tree.

PASS — The test result is in range or the commanded function works.
FAIL — The result is outside the expected condition; follow that branch.
STOP — The next step needs information/equipment not safely covered here.
Diagnostic Progress0 steps complete

Diagnostic Workpad

Write down the actual measurement before choosing PASS or FAIL. This keeps one bad assumption from steering the rest of the diagnosis.

Your notes stay in this browser on this device. They are not sent to F-Body Parts Verdict.

Ready
SETUP

Prepare the vehicle and preserve continuity

DO THIS

Fully charge/test the battery first. Key OFF, remove unnecessary plugged-in loads and arrange access so you do not keep waking the car. Use a fused bypass/test switch across the negative-battery connection so vehicle power remains continuous while the meter is introduced.

YOU SHOULD SEE

The car remains powered through the protected bypass and no large accessory load is active.

PASS → Allow the vehicle to power down.
FAIL → Correct the setup before placing a multimeter in series.
STEP 1

Let the vehicle go to sleep

DO THIS

Leave the car undisturbed through the power-down period. Do not open doors, operate switches or create another load.

YOU SHOULD SEE

The supplied Firebird procedure uses a 15-minute power-down period before the low-current decision.

PASS → Proceed to the current measurement.
FAIL → If the car is awakened, restore the bypass and restart the sleep period.
STEP 2

Measure key-off current safely

DO THIS

Start on the meter’s high-current range and correct current input. Once current is proven low enough, open the protected bypass so current flows through the meter and step down to a more sensitive range only when safe.

YOU SHOULD SEE

Current is at or below the allowable limit calculated from the battery reserve-capacity rating.

PASS → Parasitic draw is acceptable under this procedure.
FAIL → Re-establish the protective bypass before removing fuses and continue to circuit isolation.
The 2002 method uses reserve capacity ÷ 4 = maximum key-off current in mA. Example: a 100-minute RC battery corresponds to 25 mA.
STEP 3

Isolate the circuit without blowing the meter fuse

DO THIS

With the protective bypass restored, remove fuses one at a time and watch for the current to return to an acceptable level. Record the fuse that changes the reading.

YOU SHOULD SEE

One fuse/circuit causes the excessive draw to disappear or the reading remains excessive and requires checking non-fused paths such as the generator.

PASS → A suspect circuit is identified. Use the exact 2002 power-distribution diagram to identify every load on that fuse.
FAIL → Do not replace a component just because its fuse changed the reading; the fuse identifies the circuit, not the failed load.
Tool for this test
↑ Back to top← Back to diagnostic tree
Before choosing a branch: put the measurement or observation in the workpad above. Then choose PASS or FAIL from the result you actually got.

Take the result back to Battery-Drain Diagnosis

Use the result you actually got. Don’t jump to a different branch because it sounds more likely.

TEST PASSEDKey-off current is within the calculated limit → parasitic draw passes this procedure →TEST FAILEDCurrent exceeds the limit → isolate the circuit with the protected bypass restored →
After a repair: repeat the test that failed before calling the car fixed. Then verify the original symptom is gone.