ECM - One Board or Two Board Usage
Model Year 1983Bulletin No. 83-152A
File in Group 64A
Number 18A
Date July '83
SUBJECT: ONE BOARD ECM USAGE
MODELS AFFECTED: 1983-1/2 SKYLARK MODELS EQUIPPED WITH 2.5L EFI ENGINE AND AUTOMATIC TRANSMISSION (2.39 FINAL DRIVE RATIO)
NOTICE: This bulletin supersedes Bulletin 83-152, File Group 64A, #18, to correct the word now underlined in Step 3. Please discard original and replace it with this one.
On May 2, 1983, a new one board ECM went into production for 1983 Skylark models with the 2.5L engine and automatic transmissions with 2.39 final ratio.
ONE-BOARD ECM (Controller)
Service #1226156
ECM (Calibrator-PROM)
Service #1226561
The one and two-board ECM's are NOT interchangeable and will be noted as either a "one-board" or "two-board" ECM in the parts catalog. Additional service concerns are as follows:
1. Initially, one-board replacement ECM's will not have the production (OEM) part number or the PROM broadcast code printed on the label. It is important that this information is carried over onto the new ECM.
FIGURE 1:
FIGURE 2:
2. The power steering pressure switch will not be used in the air conditioning clutch control circuit on one-board ECM equipped vehicles. Diagnosis Chart 9 (Figure 1 and 2) must be used for these vehicles.
FIGURE 3:
3. The power steering pressure switch will now be used as a completely separate input to the ECM. This input will be used to anticipate high power steering loads in order to maintain a constant engine speed. Chart 11B (Figure 3) must be used for diagnosis of this system.
NOTICE: Part Number 1226561, PROM, will be available from WDDGM after July 18, 1983.